U.S.NAVY UNDERWATER SHIP HUSBANDRY MANUAL

CHAPTER 11

WET AND DRY CHAMBER WELDING

TABLE OF CONTENTS

SAFETY SUMMARYSECTION 1 - INTRODUCTION11-1.1 PURPOSE11-1.2 SCOPE11-1.3 APPLICABILITY

SECTION 2 - REFERENCES11-2.1 REFERENCES

SECTION 3 - DEFINITIONS11-3.1 DEFINITIONS11-3.1.1 Ambient Pressure11-3.1.2 Amperage11-3.1.3 Arc Voltage11-3.1.4 Austenitic Filler Metal11-3.1.5 Backgouging11-3.1.6 Background Gas11-3.1.7 Backing11-3.1.8 Base Metal11-3.1.9 Bevel Angle11-3.1.10 Carbon Equivalent (CE)11-3.1.11 Confirmation Weld11-3.1.12 Defect Terminology11-3.1.13 Direct Visual Examination11-3.1.14 Dry-Backed Weld Joint11-3.1.15 Dry Chamber Welding11-3.1.16 Essential Variables11-3.1.17 Expansion Area11-3.1.18 Filler Metal11-3.1.19 Fillet Weld11-3.1.20 Fillet Weld Size11-3.1.21 Gages11-3.1.22 Groove Weld11-3.1.23 Ground Connection11-3.1.24 Heat-Affected Zone11-3.1.25 Hyberbaric Conditions11-3.1.26 Inadvertent Inspection11-3.1.27 Indirect Visual Examination11-3.1.28 Inspection Area11-3.1.29 Interpass Temperature11-3.1.30 Joint Root11-3.1.31 Open Circuit Voltage11-3.1.32 Permanent Repair11-3.1.33 Polarity11-3.1.34 Preheat Temperature11-3.1.35 Root Layer11-3.1.36 Shielded Metal Arc Welding (Stick Welding)11-3.1.37 Snipe11-3.1.38 Suitable Scale11-3.1.39 Temporary Repair11-3.1.40 Weld Bead11-3.1.41 Weld Defect11-3.1.42 Weld Discontinuity11-3.1.43 Weld Face11-3.1.44 Welder-Diver11-3.1.45 Welding System11-3.1.46 Weld Layer11-3.1.47 Weld Pass

11-3.1.48 Weld Throat11-3.1.49 Weld Toe11-3.1.50 Wet-Backed Weld Joint11-3.1.51 Wet Welding11-3.1.52 Workmanship Samples

SECTION 4 - GENERAL APPLICATION OF UNDERWATER WELDING11-4.1 METHODS OF UNDERWATER WELDING.11-4.1.1 Wet Underwater Welding11-4.1.2 Dry Chamber Underwater Welding11-4.2 REPAIR CLASSIFICATION.11-4.3 THIRD-PARTY MONITORING AND CERTIFICATION.

SECTION 5 - UNDERWATER WELDING EQUIPMENT11-5.1 GENERAL11-5.2 WELDING POWER SUPPLIES11-5.2.2 Engine or Motor-Driven Generators11-5.2.3 Transformer-Rectifiers11-5.2.4 Inverters11-5.3 MAINTENANCE OF UNDERWATER WELDING EQUIPMENT11-5.3.1 DC Generators11-5.3.2 Transformer-Rectifiers11-5.3.3 Inverters11-5.4 WELDING CABLES, SAFETY SWITCHES, AND ELECTRODE HOLDERS11-5.4.1 Welding Cables11-5.4.2 Safety Switches11-5.4.3 Wet Welding Electrode Holders11-5.5 AMPERAGE AND VOLTAGE METERS11-5.5.1 Amperage Meters11-5.5.2 Voltage Meters11-5.6 WELD CLEANING AND GRINDING EQUIPMENT11-5.6.1 Grinders11-5.6.2 Chipping Hammers and Needle Guns11-5.6.3 Power Sources11-5.7 DRY CHAMBERS11-5.8 WELDING FILLER METAL11-5.8.1 Wet Welding Electrodes11-5.8.2 Dry Chamber Welding Electrodes

SECTION 6 - PROCEDURE AND PERFORMANCE QUALIFICATION11-6.1 GENERAL11-6.2 WELDING PROCEDURE QUALIFICATION11-6.2.2 UWDC Welding Procedure Qualification11-6.2.3 Wet Welding Procedure Qualification11-6.3 WELDING PERFORMANCE QUALIFICATION11-6.3.1.1 UWDC Welding Performance Qualification11-6.3.1.2 Wet Welding Performance Qualification11-6.4 WELDING POSITION LIMITATIONS11-6.5 MAINTENANCE OF PERFORMANCE QUALIFICATION11-6.6 CONFIRMATION WELD

SECTION 7 - REPAIR PROJECT PLANNING11-7.1 INITIAL PLANNING11-7.2 UNDERWATER WELDING REPAIR WORK PACKAGE11-7.2.2 Description of Work11-7.2.3 Records11-7.2.4 Approval11-7.3 JOB COORDINATION11-7.4 JOB DOCUMENTATION

SECTION 8 - WELDING TECHNIQUES11-8.1 GENERAL11-8.2 PUDDLE CHARACTERISTICS AND WELD DISCONTINUITIES11-8.3 POSITIONS OF WELDING11-8.4 COMMON WET WELDING PROBLEMS11-8.5 ARC BLOW AND MAGNETIC FIELDS

SECTION 9 - INSPECTION OF WELDMENTS11-9.1 GENERAL11-9.2 VISUAL TESTING (VT)11-9.3 LIQUID PENETRANT TESTING (PT)11-9.4 MAGNETIC PARTICLE TESTING (MT)11-9.5 RADIOGRAPHIC TESTING (RT)11-9.6 ULTRASONIC TESTING (UT)11-9.7 EDDY CURRENT TESTING (ET)11-9.8 LIMITATIONS11-9.9 GENERAL APPLICATION

SECTION 10 - TROUBLESHOOTING11-10.1 INTRODUCTION11-10.2 COMMON WELDING PROCESS PROBLEMS11-10.3 COMMON WELDING QUALITY PROBLEMS11-10.4 ARC BLOW AND MAGNETIC FIELDS11-10.5 BASE METAL CRACKING WITH RESPECT TO ELECTRODE TYPE11-10.6 POWER SUPPLY PROBLEMS11-10.7 ELECTRICAL CIRCUIT PROBLEMS11-10.8 ADDITIONAL CONSIDERATIONS11-10.8.1 Cathodic Protection Systems11-10.8.2 Geographic Variations In Magnetic Fields11-10.9 TROUBLESHOOTING SUMMARY

SECTION 11 - UNDERWATER WELDING WORKMANSHIP11-11.1 GENERAL11-11.2 VISUAL INSPECTION11-11.3 VISUAL INSPECTION STANDARDS11-11.4 SURFACE FINISH AND CONTOUR11-11.5 REPAIR OF WELD DEFECTS11-11.6 VERIFICATION SIGNATURE11-11.7 TRAINING/SKILLS11-11.8 RECORDS11-11.9 VISUAL INSPECTION AND ACCEPTANCE CRITERIA11-11.9.1 General11-11.10 GENERAL VISUAL INSPECTION REQUIREMENTS11-11.11 VISUAL INSPECTION PRIOR TO WELDING11-11.11.1 Base Material11-11.12 VISUAL INSPECTION OF FIT-UP11-11.13 VISUAL INSPECTION DURING WELDING11-11.13.3 Backgouge11-11.14 VISUAL INSPECTION AFTER WELD COMPLETION11-11.14.6 Grind Undercut11-11.14.9 Surface Condition11-11.14.10 Cracks11-11.14.11 Burn Through11-11.14.15 Slag11-11.14.16 Porosity11-11.14.17 Stud Welds11-11.15 REPAIRS11-11.16 ATTACHMENT WELD REMOVAL AREAS

LIST OF APPENDICESAPPENDIX A - TYPICAL DRY CHAMBER WELDING EQUIPMENT LOAD-OUT LISTAPPENDIX B - TYPICAL WET CHAMBER WELDING EQUIPMENT LOAD-OUT LISTAPPENDIX C - TYPICAL UNDERWATER WELDING PROCEDURESAPPENDIX D - RECOMMENDED TRAINING PROCEDURES FOR USE IN PREPARATION

OF UNDERWATER WELDING QUALIFICATION TESTING

LIST OF ILLUSTRATIONS11-1 Laminations11-2 Examples of Reentrant Angles11-3 Weld Terminology11-4 Measuring Concave Fillet Throat Thickness11-5 Measuring Weld Leg Length (shortest leg length shall be used

to determine actual fillet weld size)11-6 Maintenance of Throat Thickness11-7 Measuring Undercut11-8 Typical Snipe in Structural Member Connection Crossing a Butt Weld11-9 Typical Snipe in Corner or Connecting Structural Member Which Intersects Two or

More Other Members11-10 Inserts, Patches and Small Plates in Plating and Structure for Surface Ships and

Other Than the Pressure Hull Envelope for Submarines11-11 New Inserts or Patches Crossing Existing Butt Welds11-12 Example of Access Hole Intersecting Existing Welds11-13 Example of Boundary Location for Welded Patch Installation11-14 Backgouged Root11-15 Examples of Weld and Grind Undercut11-16 Example of Plate Misalignment11-17 Stud Weld and Flash11-18 Repair Excavations11-19 Finished Weld ExampleD-1 Backing BarD-2 Fillet Break Testing

LIST OF TABLES11-1 References11-2 Underwater Dry Chamber Welding Procedure11-3 Wet Welding Procedure11-4 Underwater Dry Chamber Welding Performance11-5 Wet Welding Performance11-6 Common Welding Process Problems11-7 Common Welding Quality Problems11-8 Weld Leg Length Requirements11-9 Maximum Grind Undercut11-10 Plating Alignment Limits

CHAPTER 11

WET AND DRY CHAMBER WELDING

SAFETY SUMMARY

GENERAL SAFETY PRECAUTIONS

Personnel engaged in underwater welding on U.S. Navy ships shall comply with standard hot work safety precautions for forces afloat. In addition, all personnel shall be familiar with and observe safety precautions set forth in the following publications.

a. Navy Occupational Safety and Health Program Manual for Forces Afloat, OPNAVINST 5000.19 (Series)

b. Naval Ships Technical Manual (NSTM)

c. Technical/Operating manuals for equipment

d. NAVSEA 0944-LP-001-9010, U.S. Navy Diving Manual, Volume I

WARNINGS AND CAUTIONSSpecific warnings and cautions appearing in this chapter are summarized below for emphasis and review. The page number where each warning and caution appears is given in parentheses for each warning or caution. These warnings and cautions are by no means all-inclusive, and personnel should exercise logic and common sense to ensure that hazards not specifically described, caused by unusual conditions, are recognized and dealt with.

WARNINGSNever use fuel-gas burning processes in an underwater dry chamber. Using fuel-gas burning processes under pressure can cause an explosion. (page 11-10)

Using alternating current in an underwater dry chamber can be dangerous. Cramped conditions and high humidity increase the potential for electrical shock. (page 11-10)

Personnel working with or near high voltage shall be familiar with resuscitation procedures. (page 11-12)

AC power shall not be used for underwater wet welding. (page 11-12)

Ensure that the welding machine frame and supporting structure are properly grounded before starting welding. (page 11-12)

When used for underwater welding, power supplies using auxiliary AC power should be provided with ground fault detectors to provide protection if a short occurs between the AC input and the DC output. (page 11-13)

Welding cables should be strung separate and apart from any underwater cable that is AC supplied. (page 11-15)

A positive-acting, unfused current interrupt switch (ground fault interrupter) must be part of the welding circuit when using an AC-supplied power source. This protects the welder-diver should a short occur between the AC and DC circuits of the power supply. (page 11-15)

Never take pneumatic tools with in-line lubricators into the chamber. (page 11-18)

Fumes from penetrants and cleaners can be flammable and can create both a fire and a breathing hazard. All safety precautions for these substances must be read and understood. (page 11-18)

Never bring oxygen into the chamber, and never substitute oxygen for breathing air in the chamber. (page 11-18)

During wet welding, bubbles rising to the surface carry explosive gases such as oxygen and hydrogen. They can also carry small particles of glowing slag. Care shall be taken to ensure that there are no voids (i.e., sea chest openings) above the welding where the rising bubbles can displace the water and thus cause an explosion. (page 11-30)

Nitric acid can cause serious burns and shall be handled cautiously. When mixing acid and alcohol, the acid shall always be poured into the alcohol. (page D-4) Materials used with liquid penetrant inspection are flammable and must be used with caution in a dry chamber. (page 11-31)

CAUTIONSDo not use emery cloth to clean commutators. Emery is a conductor of electricity, and residual particles can short-circuit the commutator. (page 11-13)

Ensure that all tools and materials brought to the underwater job site are accounted for and removed at the completion of the job. Tools and material inadvertently left at the job site can generate unacceptable noise and possibly cause severe damage to shipboard components. Locally generated work packages shall ensure that a general tool and material log sheet is prepared and maintained during all UWSH operations. (page 11-25)

SECTION 1 - INTRODUCTION

11-1.1 PURPOSE.The purpose of this chapter is to provide information to the Fleet in the application of underwater welding techniques and methods. This information is intended for use by both civilian and military personnel associated with the planning, direction, performance, and inspection of underwater work.

11-1.2 SCOPE.

The information in this chapter applies to underwater welding using both the wet welding method and the dry chamber welding method. These underwater welding methods are addressed in terms of the following:

a. Personnel training

b. Procedure and personnel qualification

c. Applications and techniques

d. Equipment and materials

e. Inspection requirements and methods

11-1.3 APPLICABILITY.

All methods, techniques, and principles described in this chapter are applicable to repairs to both active and inactive U.S. Navy surface ships and submarines.

NOTEThere are no preapproved repair applications for submarines.

Any repair to a submarine must be specifically approved by NAVSEA.

11-1.3.1 This chapter is intended for use with the applicable references of section 2. The primary document for use with this chapter is Chapter 074 of the Naval Ships’ Technical Manual (NSTM), section 6; where conflicts exist between this chapter and NSTM Chapter 074, the requirements of Chapter 074 take precedence. Other section 2 documents are to be used as invoked in Chapter 074. One document of importance is the American Welding Society Specification for Underwater Welding (ANSI/AWS D3.6). Another very important document, covering practical aspects of underwater cutting and welding, is NAVSEA 0910-LP-111-3000, U.S. Navy Underwater Cutting and Welding Manual.

SECTION 2 - REFERENCES

11-2.1 REFERENCES.

11-2.1.1 The documents in Table 11-1, as applicable, shall be used by personnel involved in underwater welding operations associated with Naval ship repair. The latest issue of these documents shall be used unless otherwise specified.

11-2.1.2 While not all the documents are referenced in this chapter, they are referenced in NSTM Chapter 074, which is the governing document covering the application of under-water welding.

SECTION 3 - DEFINITIONS

11-3.1 DEFINITIONS.

Definitions presented herein are related specifically to welding. A more complete presentation of welding definitions is provided in ANSI/AWS A3.0 for surface (topside) welding and ANSI/AWS D3.6 for underwater welding. Other documents, referenced herein, also contain definitions appropriate for those particular documents. Although the terms defined below are also defined in some of the referenced documents, they are considered especially useful for work covered by this chapter.

11-3.1.1 Ambient Pressure. Pressure of the water at the depth of welding.

11-3.1.2 Amperage. The electrical current flowing through the welding circuit.

11-3.1.3 Arc Voltage. The voltage across the welding arc.

11-3.1.4 Austenitic Filler Metal. Refers to welding filler metal that is nonmagnetic and highly corrosion resistant (e.g., chromium nickel welding electrodes of MIL-E-22200/2).

11-3.1.5 Backgouging. The removal of weld metal and base metal on the backside of the root layer of full penetration welds to the extent necessary to permit proper deposition of weld metal on the second side to achieve complete penetration. The reverse side of a full penetration weld is inspected after welding from one side and grinding the reverse side to sound metal (free of keyholes) and prior to welding from the backgouged side. Back-gouge preparation shall allow full weld joint access.

11-3.1.6 Background Gas. Gas that displaces water in a dry chamber. For purposes of this document, the gas is diver breathable.

11-3.1.7 Backing. Base metal or weld metal backing, at the backside of a weld joint, intended to prevent burn-through during welding.

11-3.1.8 Base Metal. The metals to be joined by welding.

11-3.1.9 Bevel Angle. The angle of the sides of a groove weld joint.

11-3.1.10 Carbon Equivalent (CE). A formula, based on base metal chemistry, indicating the sensitivity of that particular base metal to hydrogen-induced underbead cracking as a result of welding. The formula is expressed as follows where the values for the elements are in weight percent:

a. CE = C + Mn/6 + (Cr+Mo+V)/5 + (Cu+Ni)/15 or, when only the carbon and manganese are known, CE = C + Mn/6 + 0.05

11-3.1.11 Confirmation Weld. A test weld made at the underwater work site prior to production welding. The confirmation weld is intended to demonstrate proper functioning of the welding system (e.g., power supply, welding leads, and stinger) and welding ability of the welder/diver for the given environmental conditions (e.g., wave action, visibility, current). It is not intended to be used as requalification of the welding procedure and/or welder.

11-3.1.12 Defect Terminology.

a. Arc Strike. Any localized heat-affected zone or change in the contour of the surface of the finished weld or adjacent base metal resulting from an arc or heat generated by the passage of elec-trical energy between the surface of the finished weld or base metal and a current source, such as welding elec-trodes, magnetic particle inspection electrodes (prods), etc.

b. Burn-Through. A void or open hole on the inner surface, extending through a backing strap, fused root, or adjacent base metal resulting from fusion completely through a localized region.

c. Crack. A linear rupture or fracture type discontinuity or tear.

d. Crater Pit. An approximately circular pipe hole open to either surface of a weld in which the bottom cannot be seen or determined. Crater pits are normally found in the weld crater at the end of a weld increment (weld craters are round bottom depressions at weld stops).

e. Incomplete Fusion. Lack of complete fusion of some portion of the metal in the weld joint with adjacent metal. The adjacent metal may be either base metal or previously deposited weld metal.

f. Incomplete Penetration. Lack of fusion through the thickness of the joint. A portion of the weld end preparation has been left in its original state.

g. Laminations. A visual or NDT linear indication disclosed on a plate edge that lies essentially parallel to the plate surface (see Figure 11-1).

h. Melt-Through. An irregularity on the inner surface of a backing strap, fused root or adjacent base metal resulting from fusing completely through a localized region but without development of a void or open hole. Concavity with a uniform radius and bottom surface completely visible in a melt-through area shall not be considered a void or open hole.

i. Overlap. A condition where weld metal covers the base material surface but is not fused to the base material. A condition similar to the area less than 90° shown in the re-entrant angle example weld of Figure 11-2.

j. Porosity. Gas pockets or voids in a weld or casting.

k. Re-Entrant Angle. The angle formed by the weld and base metal intersection after welding. Re-entrant angle shall be 90° or more to be acceptable (see Figure 11-2).

l. Root Undercut. A groove on the internal surface of the base metal or backing strap along the edge of the weld root.

m. Slag. Nonmetallic solid material adhering to or entrapped between beads of weld metal or between weld metal and base metal.

n. Weld Spatter. Metal particles expelled during welding that deposit on the surface of the weld or adjacent base metal during welding and that do not form a part of the weld. Weld spatter may be tightly adherent or loose.

o. Weld Undercut. A groove melted into the base metal at the toe of the weld and left unfilled by weld metal.

p. Grind Undercut. A groove made at the edge or toe of a weld (or other repair area) caused or made by grinding below the weld or base material surface. Grind undercut acceptance applies to weld undercut after grind repair.

11-3.1.13 Direct Visual Examination. Visual examination of a weld, performed directly at the weld.

11-3.1.14 Dry-Backed Weld Joint. A weld joint for which the backside is not in contact with water for a distance of at least 6 inches from the joint.

11-3.1.15 Dry Chamber Welding. Underwater welding in air at ambient pressure in an open-bottomed dry chamber from which water has been displaced.

11-3.1.16 Essential Variables. Those elements (e.g., amperage, filler metal) of a welding procedure that may affect its performance. These elements are an essential part of the welding procedure, and any change in the elements requires requalification of the procedure.

11-3.1.17 Expansion Area. An expansion area is the area (including welds) adjacent to the new weld area that requires NDT in accor-dance with NSTM 074, Volume 1.

11-3.1.18 Filler Metal. The metal (i.e., the covered electrode in shielded metal arc welding) used to fill a weld joint.

11-3.1.19 Fillet Weld. A weld that has a triangular cross section, joining two surfaces that are perpendicular to each other (i.e., lap joint, tee joint, corner joint).

11-3.1.20 Fillet Weld Size. The length of the fillet weld leg(s), measured from one base metal surface to the toe of the weld on the other base metal surface.

11-3.1.21 Gages. The word “gage” as used in this manual means all measuring devices (tools, gages, instruments, scales, etc.) used to inspect and accept material and work.

11-3.1.22 Groove Weld. A weld made in the groove between two members to be joined.

11-3.1.23 Ground Connection. The electrical connection between the piece to be welded and the welding cable.

11-3.1.24 Heat-Affected Zone. That portion of the base metal, adjacent to the weld fusion line, having its metallurgical structure changed by the heat of welding.

11-3.1.25 Hyberbaric Conditions. Pressure conditions that are greater than atmospheric (surface) pressure.

11-3.1.26 Inadvertent Inspection. Inspection of a condition observed in areas beyond the required inspection boundary.

11-3.1.27 Indirect Visual Examination. Visual examination of a weld using photographs, video coverage, or other approved remote methods (as opposed to direct visual examination).

11-3.1.28 Inspection Area. The defined area within which a specified nondestructive test is conducted. The inspection areas are delineated in the applicable nondestructive test procedures (e.g., VT, MT, PT, RT, UT, and ET).

a. Defect Area. The actual defective area of a weld or base material detected by nondestructive testing.

b. Repair Area. Repair areas are in two categories:

(1) Grind Repair Area. The total area ground out.

(2) Weld Repair Area. Repair area on which weld is deposited. This is not limited by the defect area (e.g., if repair of a defect area 1/4 inch long requires a grind-out and reweld 1 inch long, the repair area is 1 inch long).

11-3.1.29 Interpass Temperature. The weldment temperature measured between weld passes just prior to beginning a new weld pass.

11-3.1.30 Joint Root. That area of a weld joint just beneath the first weld pass.

11-3.1.31 Open Circuit Voltage. The voltage measured between the positive and negative leads of a welding circuit (or across the welding power supply terminals) when the power supply is energized but no welding is taking place; the no load voltage.

11-3.1.32 Permanent Repair. For underwater welding, a repair to a Naval vessel that does not require rework.

11-3.1.33 Polarity. That which controls the direction of current flow in a direct current (DC) welding circuit as follows:

a. Direct current electrode positive (DCEP). The electrode holder (stinger) cable is connected to the positive terminal of the welding power supply (formerly called “reverse polarity”).

b. Direct current electrode negative (DCEN). The electrode holder (stinger) cable is connected to the negative terminal of the welding power supply (formerly called “straight polarity”).

11-3.1.34 Preheat Temperature. The measured temperature of the base metal, at the weld joint, just prior to the start of welding.

11-3.1.35 Root Layer. The layer (one or more beads) which initially joins the base materials (see Figure 11-3).

11-3.1.36 Shielded Metal Arc Welding (Stick Welding). An arc welding process using a flux-covered metal electrode. The electrode provides the filler metal. The molten filler metal is protected from the atmosphere by the gases and slag produced by decomposition of the flux.

11-3.1.37 Snipe. A cut-off or cut-out in the plate to provide access for making welds under the snipe.

11-3.1.38 Suitable Scale. A scale with increments of 1/64 inch.

11-3.1.39 Temporary Repair. An underwater welding repair to a Naval vessel that must be reworked within a specified time.

11-3.1.40 Weld Bead. A weld resulting from a pass.

11-3.1.41 Weld Defect. A weld discontinuity that fails to meet inspection standards.

11-3.1.42 Weld Discontinuity. Any imperfection in a weld. It may be either acceptable or rejectable per the applicable inspection standards.

11-3.1.43 Weld Face. The exposed surface of a weld on the side from which the welding was performed (see Figure 11-3).

11-3.1.44 Welder-Diver. A person qualified in accordance with this chapter to perform underwater welding.

11-3.1.45 Welding System. The welding power supply, leads, electrode holder, and electrodes required to perform underwater welding.

11-3.1.46 Weld Layer. One or more adjacent weld passes.

11-3.1.47 Weld Pass. A single progression of welding along a joint. The result of a pass is a weld bead or layer. A pass may include several stops and starts.

11-3.1.48 Weld Throat. The shortest distance between the weld root and the weld face.

11-3.1.49 Weld Toe. The edge of the weld surface at the base metal.

11-3.1.50 Wet-Backed Weld Joint. In a dry chamber, a weld joint for which the backside is in contact with water 6 inches or less from the weld joint.

11-3.1.51 Wet Welding. Underwater welding where there is no mechanical barrier between the welding arc and the water.

11-3.1.52 Workmanship Samples. Photos, molded plastic samples or other visual aid used to compare to the surface condition.

SECTION 4 - GENERAL APPLICATION OF UNDERWATER WELDING

11-4.1 METHODS OF UNDERWATER WELDING.

This chapter covers two methods of underwater welding. Both methods are addressed in detail below. Although a number of welding processes are used for underwater welding, the shielded metal arc welding process is the only process presently allowed for Navy work using the underwater welding methods described below.

11-4.1.1 Wet Underwater Welding. Wet underwater welding (wet welding) is the simplest and least expensive of the underwater welding methods. In terms of welding equipment, all that is needed is a power supply, welding leads, an electrode holder, and welding electrodes. With this method, the only barrier between the welding arc and the water is the bubbles generated at the arc during welding; most of these bubbles result from gases being given off as the electrode coating (flux) decomposes in the heat of the welding arc. Although these bubbles are essential for the welding, they present certain problems, discussed further in section 8.

11-4.1.1.1 Although wet welding can be applied to many types of base metals, carbon steels and 300 series (chromium-nickel) aus-tenitic stainless steels are the only base metals for which wet welding data has been developed to any significant extent. Currently available wet welding electrode material types are carbon steel, austenitic stainless steel, and high nickel. Guidelines concerning the application of these electrodes are given below.

11-4.1.1.2 Carbon steel electrodes can be used for welding carbon steel base metals with a carbon equivalent (see definition in section 3) not exceeding 0.40. When these electrodes are used for welding carbon steel base metals with a carbon equivalent greater than 0.40, there is a good chance that hydrogen induced underbead cracking will occur in the heat-affected zone of the base metal. To avoid this problem, use either austenitic stainless steel or high-nickel electrodes instead.

11-4.1.1.3 Austenitic stainless steel electrodes are to be used when welding austenitic stainless steel base metals. They may also be used for welding carbon steel base metals with a carbon equivalent greater than 0.40. However, when used on the higher carbon equivalent carbon steels, the maximum weld thickness (the shortest distance between the joint root and the weldface) allowed is 3/8 inch. Thicker welds have been shown to cause diffusion zone cracking at the weld fusion line.

11-4.1.1.4 High-nickel electrodes may also be used for welding carbon steel base metals with a carbon equivalent greater than 0.40. There is no limitation on weld thickness when using these electrodes.

11-4.1.1.5 Guidelines for obtaining chemistries for determining the carbon equivalent are shown in ANSI/AWS D3.6 as invoked in NSTM Chapter 074, Volume 1.

11-4.1.1.6 Since weldments produced by wet welding lack the toughness and ductility of those produced in air, wet welding use for Naval ship repair is limited. Section 6 of NSTM Chapter 074, Volume 1, provides wet welding applicability guidelines.

11-4.1.2 Dry Chamber Underwater Welding. Underwater dry chamber (UWDC) welding requires the use of a dry chamber to enclose the area to be welded. See also paragraph 11-5.7.

11-4.1.2.1 The chamber shall be designed in accordance with the requirements of Chapter 16 of the Underwater Ship Husbandry Manual. The chamber must be blown dry using diver-breathable air. Once the water in the chamber is displaced with air, there will be a significant positive buoyancy. Therefore, chamber design and rigging equipment must be capable of withstanding the buoyancy forces. Additional information on chamber design is contained in section 6 of NSTM Chapter 074, Volume 1, and section 5 of this chapter.

11-4.1.2.2 UWDC welding is similar to welding topside, except the pressures at depth tend to constrict the welding arc. Therefore, some adjustment to welding technique is required; this is addressed in more detail in section 8 of this chapter.

WARNINGNever use fuel-gas burning processes in an underwater dry chamber. Using fuel-gas burning processes under pressure

can cause an explosion.

11-4.1.2.3 High humidity is always a problem in UWDC welding. Weld joint surfaces that are left wet when the chamber is blown dry require heating to remove moisture, since the high humidity prevents the surfaces from drying on their own. The type of heating generally used is resistance heating pads. Fuel-gas processes are never to be used in the dry chamber.

WARNINGUsing alternating current to power electrical heating pads in

an underwater dry chamber can be dangerous. Cramped conditions and high humidity increase the potential for

electrical shock.

11-4.1.2.4 When electrical heating pads are used, direct current shall be used as opposed to alternating current to avoid the possibility of hazardous shock.

11-4.1.2.5 The high humidity can also affect the welding electrodes since the electrode flux can absorb moisture This requires limitations on electrode exposure time in the dry chamber as addressed in section 6 of NSTM Chapter 074, Volume 1, as invoked in section 6 of this chapter.

11-4.1.2.6 When accomplished using properly qualified procedures and personnel, UWDC welding is considered equivalent to welding performed topside. As a general rule, UWDC welding can be used for surface ship repair involving ordinary and higher strength steels 2 inches or less in thickness. Section 6 of NSTM Chapter 074, Volume 1, provides specific guidelines as to where UWDC welding may be used.

11-4.2 REPAIR CLASSIFICATION.

Underwater welding repairs are classified as either permanent or temporary (see definitions in section 3). UWDC welding repairs on surface ships are generally considered permanent repairs. For wet welding, the permanency of the repair depends on factors such as the base metals involved, the criticality of the structure to be repaired, and the location of the weld in the structure. Section 6 of NSTM Chapter 074, Volume 1, specifies those applications that are considered permanent repairs; other applications are considered temporary repairs unless otherwise approved by NAVSEA.

11-4.2.1 Where procedures and personnel are properly qualified as required by section 6 of this chapter, these procedures and personnel can be used to perform permanent repairs following the requirements of NSTM Chapter 074.

11-4.3 THIRD-PARTY MONITORING AND CERTIFICATION.

An independent third party activity, approved by NAVSEA, shall be obtained to monitor all procedure qualification and production underwater welding operations. The third party will verify that the requirements of the applicable specifications are met and should be able to provide technical assistance as needed. Third-party monitoring is required due to the underwater welding environment, where personnel performing the work must be dual-hatted — performing both production and quality control functions. Detail requirements for third-party monitoring are specified in NSTM Chapter 074, Volume 1.

SECTION 5 - UNDERWATER WELDING EQUIPMENT

11-5.1 GENERAL.

Proper selection and maintenance of underwater welding equipment is critical for satisfactory and efficient job completion. During topside welding projects, equipment failure and changeout generally affect only those personnel involved in the welding. During underwater welding projects, however, any delay affects the entire dive team. Therefore, any delay in an underwater welding project results in cost increases which far exceed those which would be experienced during a similar delayin a topside welding job. Because changeout of underwater equipment is more time consuming than a similar changeout top-side, proper selection and maintenance of underwater welding equipment can not be overemphasized.

11-5.1.1 Maintenance of equipment should be an ongoing job. Many times, when equipment maintenance is only considered during the planning or set up of a particular job, the maintenance either does not get done or is not done properly — resulting in job delays from equipment failure. Furthermore, underwater welding jobs are often of an urgent nature where time does not allow adequate equipment maintenance prior to the job.

11-5.1.2 This section addresses welding equipment for both wet welding and UWDC welding. The following equipment is covered (detailed equipment load-out lists are shown in Appendices A and B):

a. Welding power supplies

b. Welding cables, safety switches, and electrode holders

c. Amperage and voltage meters

d. Weld cleaning and grinding equipment

e. Dry chambers

f. Welding filler metal

11-5.2 WELDING POWER SUPPLIES.

The minimum requirements for an underwater welding shielded metal arc (stick electrode) power supply are as follows:

a. 60 volts open circuit

b. 300 amps at a 60 percent duty cycle.

NOTEMultiple-operator welding machines shall not be used.

WARNINGPersonnel working with or near high voltage shall be familiar

with resuscitation procedures.

WARNINGAC power shall not be used for underwater wet welding.

WARNINGEnsure that the welding machine frame and supporting structure are properly grounded before starting welding.

11-5.2.1 The welding power supplies addressed in 11-5.2.2 through 11-5.2.4 are acceptable for use in work governed by this chapter.

11-5.2.2 Engine or Motor-Driven Generators. DC generators may be driven by either diesel/gas engines or electric motors. The engine-driven generators do not require auxiliary electrical power, whereas the motor-driven generators require a good deal of auxiliary electrical power, such as 440 volts AC.

11-5.2.2.1 DC generators generally have two dials for control of amperage and voltage. One dial, the “job selection” or “coarse amperage range” dial, establishes the amperage range and open circuit voltage range; this dial setting should never be changed while the machine is under load. The other dial fine-tunes the amperage and open circuit voltage within the range established by the first dial. Additional information for adjustment of this type of welding machine is contained in the U.S. Navy Underwater Cutting and Welding Manual.

11-5.2.2.2 On some machines (e.g., Lincoln SAE 400) the job selection dial establishes a specific open circuit voltage, which automatically controls the maximum amperage range. The other dial fine-tunes the amperage without changing the open circuit voltage established by the first dial. This type of machine allows the operator more control over the welding characteristics, which may be of benefit during unusual welding conditions such as those associated with underwater welding.

11-5.2.3 Transformer-Rectifiers. These welding machines are powered by auxiliary 220-volt or 440-volt AC power. The auxiliary power is reduced in voltage and converted to DC for welding.

WARNINGWhen used for underwater welding, power supplies using auxiliary AC power should be provided with ground fault

detectors to provide protection should a short occur between the AC input and the DC output.

11-5.2.4 Inverters. These solid-state power supplies are small and compact, weighing well under 100 pounds. Inverters first convert 220-volt or 440-volt AC input to DC, then convert the DC to high-frequency AC, which is then reduced in voltage and converted to DC for welding.

NOTEOnly DC generator, rectifier, and inverter units designed for shielded metal arc welding (constant current units) shall be used for underwater welding. Machines designed for semi-

automatic welding (constant voltage units) shall not be used.

11-5.3 MAINTENANCE OF UNDERWATER WELDING EQUIPMENT.

Maintenance of equipment should be in accordance with manufacturer recommendations. Where such information is not available, the following guidelines should be observed.

11-5.3.1 DC Generators. Dirty commutators or improperly seated brushes can cause these machines to produce inconsistent welding characteristics. Commutators should be cleaned and polished using canvas, cambric, or other lint-free cloth. Brushes should be checked to ensure freedom of movement and firm contact with the commutator.

CAUTIONDo not use emery cloth to clean commutators. Emery is a conductor of electricity, and residual particles can short-

circuit the commutator.

11-5.3.1.1 When a DC generator is operated beyond its rated output, the soldered rotor winding connections at the commutator can melt; this can keep the machine from operating at its rated output. If this condition is suspected, the interior of the machine’s outer housing should be inspected for bits of melted solder. Repairs should be made as necessary.

11-5.3.2 Transformer-Rectifiers. These machines are not generally designed for outdoor use in an unsheltered area, so protection from the elements is important. Heavy dust deposits inside the machines can cause overheating of electrical components and should be avoided.

11-5.3.2.1 When the rectifier cells begin to break down, either from age or from overheating due to dust buildup or operating the machine beyond its rated output, the cells begin to change color to a brown or black. The wave forms of voltage across the cells can be checked using an oscilloscope. Any cell that shows a voltage wave form significantly different from the others can be considered defective, indicating that the rectifier stack containing the faulty cell should be replaced.

11-5.3.3 Inverters. These are portable units and better designed for outside use than the rectifier units. As with the rectifier units, however, heavy dust buildup inside the housing can cause overheating of electrical components. These units should be opened occasionally and cleaned, and electrical connections should be examined. It is also a good idea to spray control boards and associated electrical connections with an appropriate waterproofing material to inhibit corrosion.

11-5.4 WELDING CABLES, SAFETY SWITCHES, AND ELECTRODE HOLDERS.

Along with the welding electrode, these components carry the electrical current required for performing underwater welding. Any point in this circuit where an amperage leak or voltage drop occurs can affect successful completion of the weld. With thisin mind, each of the components is addressed below.

11-5.4.1 Welding Cables. Welding cables (electrode lead, ground lead, and electrode holder whip) shall be of the stranded copper type; the extra-flexible type is preferred. The longer the cables, the higher the voltage drop; this is why larger diameter cables are used for longer cable runs, since larger diameter cables have less voltage drop. Size 1/0 should be suitable for most jobs governed by this chapter. Where the total cable length exceeds 200 feet, size 2/0 should be used (except the stinger [electrode holder] whip may always be size 1/0 for ease of manipulation by the welder-diver). Additional information on cable sizes and voltage drops is contained in the U.S. Navy Underwater Cutting and Welding Manual.

11-5.4.1.1 In addition to cable length, voltage drops can occur wherever a significant number of the copper strands are broken or where cable lugs or connections are loose. This can cause arcing, heat buildup, and eventual failure of the cable or connection, not to mention associated inconsistencies in welding charac-teristics.

11-5.4.1.2 Welding arc voltage is read on a meter connected across the positive and negative welding cable leads near the meter, since such connections at the underwater weld site are not practical. This means that the actual arc voltage is less than that shown on the meter by the amount of voltage drop in the welding leads. When the proper size cables are used, the cables are in good repair, and cable lugs are tight, the voltage drop in the cables is not significant.

11-5.4.1.3 Welding amperage leakage can be a problem where breaks in the cable insulation occur. Current, following the path of least resistance, may travel thorough the water to a grounded structure nearby. This means that the amperage meter (which is connected in-line) may be reading inaccurately, depending on which side of the welding circuit the meter is on. On one side of the circuit, the meter reads the full amperage of the current leaving the welding machine; on the other side of the circuit, the meter only reads the amperage returning to the machine. Of course, if the exposed welding cable on the hot side of the welding circuit is touching the grounded structure, there may be a dead short and no current would be available to the welding electrode.

11-5.4.1.4 To prevent the problems discussed above, all cable connections must be tight and all cable and connections (except at the welding machine) must be properly insulated. Where breaks in the cable insulation are found, a good waterproof repair can be made using Scotchcoat-type adhesive with electrical tape.

11-5.4.1.5 Stray electrical currents are another problem that can occur in both underwater welding and surface welding. Stray currents occur when the ground lead is attached to the structure on which the welding machine is located rather than the work, which causes the welding current to return to ground through the water. When this occurs, galvanic corrosion can take place on either the work structure or the structure on which the welding machine is located, depending on the welding polarity being used (see section 8 and paragraph 11-5.4.3 below dealing with electrode holders). Stray currents, to a lesser degree, can also occur when the ground lead is grounded to earth at the welding machine or at some point between the welding machine and the work. This allows two ground paths: one through the welding cable and the other through the water. The ground-return cable connection should be located as close to the work as possible. Ground-return cable connections should be no farther than 10 feet from the work and preferably where the connection can always be seen by the welder-diver. This ensures that the welding current does not flow through bearings, threaded joints, and other areas where arcing could occur. Adherence to the proper connection of the ground return cable, use of a welding machine which meets the requirements of the National Electrical Code, and use of properly insulated cable will prevent a stray current problem.

11-5.4.1.6 Welding cable layout topside can influence welding characteristics. If excess cable is coiled, fluctuations in welding current cause electric fields in the coils; these fields interfere with the flow of current to the weld. Excess cable should be laid out in straight lines, in the shape of a “U,” or in a figure-eight pattern. Additional information on welding cables and their arrangement is presented in the NSTM Chapter 074, Volume 1.

WARNINGWelding cables should be strung separate and apart from any

underwater cable that is AC supplied.

11-5.4.2 Safety Switches. Safety switches shall always be used in the welding circuit. These switches may be of the electrical con-tactor type or the knife switch type, and they should remain open except when welding is actually taking place. When knife switches are used, the double-pole type is required. Regardless of the type used, the safety switch must be rated to carry the maximum welding current and should be rated to carry the maximum current of the welding power supply. Additional requirements for knife switches are covered in the U.S. Navy Underwater Cutting and Welding Manual.

WARNINGA positive-acting, unfused current interrupt switch (ground fault interrupter) must be part of the welding circuit when

using an AC-supplied power source. This protects the welder-diver if a short occurs between the AC and DC circuits of the

power supply.

11-5.4.3 Wet Welding Electrode Holders.

Electrode holders should be of the commercially available type specifically designed for underwater welding. At the end of each dive, the head of the holder should be removed and all current conducting parts should be examined for deterioration. The metal components of an electrode holder deteriorate with time. However, their deterioration (galvanic corrosion) can be accelerated when the holder is on the positive side of the welding circuit; in this situation, metal ions migrate toward the negative pole causing a corrosion of the metal in the holder. This action can be greatly reduced by keeping the safety switchopen at all times other than when welding is actually taking place.

11-5.4.3.1 The security of the whip-to-holder connection should also be occasionally checked. A breakdown of the copper strands will cause the same problems described for welding cables. Refer to the U.S. Navy Underwater Cutting and Welding Manual for additional information on electrode holders.

11-5.5 AMPERAGE AND VOLTAGE METERS.

These meters can be either of the analog or digital type. The digital meters maintain their calibration better, since they are not as sensitive to vibrations due to jarring. Most digital meters also have the advantage of not having to have their leads reversed when there is a change in welding polarity. As specified in section 6 of NSTM Chapter 074, Volume 1, the digital-type meters are required when they are portable or are mounted in portable facilities.

11-5.5.1 Amperage Meters. These are inline meters. However, the meter sees only a measured amount of current through a shunt; this current is actually read in millivolts and displayed on a graduated amperage scale. Location of the meter in the welding circuit is discussed in 11-5.4.1 above. The tong test ammeter is a handy handheld meter that measures the amperage based on the electric field surrounding the welding cable. This meter is described in detail in the U.S. Navy Underwater Cutting and Welding Manual. An amperage meter for underwater welding should have a range of 0-400 amps.

11-5.5.2 Voltage Meters. Voltage meters are connected across the positive and negative leads of the welding circuit. They measure the welding machine open circuit voltage when the safety switch is open. When the switch is closed, the arc voltage is measured (the open circuit voltage minus the internal load voltage drop of the welding machine). A volt meter for underwater welding should have a range of 0-150 volts.

11-5.6 WELD CLEANING AND GRINDING EQUIPMENT.

Hand wire brushes and chipping hammers should always be part of the welder-diver’s gear. In addition, powered equipment is essential for efficient completion of many jobs. The following powered equipment may be considered for underwater weld cleaning and grinding.

11-5.6.1 Grinders. Grinders can be used with either grinding wheels or wire brush wheels. The wire brushes offer a fast method of slag removal, with the disadvantage that the bristles can not reach slag trapped in deep weld valleys or undercuts. Grinding wheels can remove surface slag as well as entrapped slag; they also allow any necessary weld bead contouring prior to depositing the next weld bead.

11-5.6.1.1 Grinding wheel thicknesses of 3/16 inch to 1/4 inch are good for general weld cleaning and grinding. Wheels of 1/8 inch thickness are more effective for fast metal removal over a small area and allow better control in weld defect removal. Grinders should be capable of operating at 3000-8000 rpm at depth. It should be noted that wire wheels offer more resistance in the water than grinding wheels, so grinders should be selected that have the power to drive both types of wheels.

11-5.6.2 Chipping Hammers and Needle Guns. Chipping hammers and needle guns both offer fast and efficient means of weld cleaning. Chipping hammers offer the additional advantage of removal of small weld surface defects.

11-5.6.3 Power Sources. Air-driven (pneumatic) units can be used, provided the air supply is sufficient to meet the unit’s power requirements and overcome the ambient pressure at depth. Pneumatic units to be used in the wet should always be operated with an inline oiler. The units should be disassembled at the end of each day and allowed to soak in oil. All pneumatic tools have the disadvantage of releasing large volumes of air bubbles which can hinder the welder-diver’s visibility of the work.

11-5.6.3.1 Hydraulic units require less maintenance and produce no air bubbles to hinder visibility of the work. Most hydraulic units require an oil flow of 8-10 gpm.

11-5.6.3.2 Water-driven units are also available commercially. These units use the water at the site and produce no air bubbles to hinder visibility of the work.

11-5.7 DRY CHAMBERS.

For purposes of underwater welding, a dry chamber is simply a box that is enclosed on all sides but two: the side fitting against the ship and the bottom side which permits entry by the welder-diver. Once the chamber is in place and sealed, the water is forced out of the bottom of the chamber by air pressure. Design, fabrication, and handling of the dry chamber requires experience that can not be covered in detail in this section. For further information refer to Cofferdams, NAVSEA S0600-AA-PRO-160. However, the following guidelines are offered:

a. Dry chambers may be constructed of metal or fire-retardant wood.

b. The chamber must be rigid enough to withstand pressure differentials, buoyant forces, and handling forces.

c. The chamber must be properly sealed against the ship’s hull as described in section 4.

d. The chamber must be large enough to incorporate the repair area plus 6 inches toward chamber walls and at least 36 inches between the lower most portion of the weld and the air-water interface at the bottom of the chamber. The chamber must be large enough to accommodate at least the upper part of the welder-diver’s body from the waist up, and all tools and preheating equipment required for the job. There should also be room enough for a video camera when required.

e. The chamber must have adequate lighting. Lighting can be enhanced by painting the inside of the chamber white using a paint approved for such use.

f. The chamber must have a vent valve for removal of welding fumes.

g. The chamber must have an adequate supply of diver-breathable air (separate from the diver’s air supply) to replace air lost due to leakage and venting of welding fumes. A muffling device for incoming air will aid in diver communications.

h. The chamber must have enough shelf area for storing dry rags, gloves, consumables, and other gear. All shelves should be constructed using material that does not trap water or gas (e.g., expanded metal).

i. The chamber must have quick closure valves on all hose/piping openings to allow the welder-diver to operate the valves in case of flooding.

j. Staging must be built inside or below the chamber to support the welder-diver.

k. Recognize that air under pressure increases the partial pressure of oxygen which increases the flammability of the environment. With this in mind, the following warnings are appropriate:

WARNINGNever take pneumatic tools with in-line lubricators into the

chamber.

WARNINGFumes from penetrants and cleaners can be flammable and

can create both a fire and a breathing hazard. All safety precautions for these sub-stances must be read and

understood.

WARNINGNever bring oxygen into the chamber, and never substitute

oxygen for breathing air in the chamber.

11-5.7.1 Dry chambers can be designed as simple boxes with all support equipment operating separately from the chamber or they can be designed with electrical, pneumatic, and hydraulic equipment interfaces at chamber penetrations. The chamber design depends on the job complexity and the repeatability of the job.

11-5.8 WELDING FILLER METAL.

Underwater welding under the auspices of this chapter shall only be accomplished using shielded metal arc electrodes (stick electrodes). Electrodes that have been approved by NAVSEA for use in Naval ship repair are defined below. Use of welding electrodes other than those defined herein will require NAVSEA approval based on NAVSEA specified welding procedure qualification testing by the requesting activity.

11-5.8.1 Wet Welding Electrodes. The following electrodes are approved for Naval ship repair based on qualification testing conducted under the direction of NAVSEA.

AWS Commercial

Classification Classification

1. 1/8" E7014 BROCO Sof Touch

(mild steel) UW-CS-1 (Note 1)

2. 1/8" E312-16 BROCO UW-SS-1 (Note 2)

NOTE1. Ordinary strength steels with a carbon equivalent of 0.40 or

less. It is recommended that the carbon equivalent be less than 0.38 when the water temperature is less than 50°F.

2. Stainless steel, and carbon steel with a carbon equivalent greater than 0.40. Maximum weld thickness shall not exceed

3/8 inch.

11-5.8.1.1 A 3/32-inch, high-nickel wet welding electrode, designated as Sandvik Aqua San 5A, is currently being evaluated by NAVSEA. This electrode may be used for welding carbon steels with a carbon equivalent of 0.40 and higher when approved by NAVSEA. The type of waterproof coating used in this application shall also be approved by NAVSEA.

11-5.8.1.2 All wet welding electrodes have a waterproof coating. The integrity of this coating should be examined prior to welding. All electrodes that have a damaged coating should be discarded.

11-5.8.1.3 Where there is a question of the integrity of the waterproof coating, sample electrodes can be exposed to the water for about 5 minutes; if the electrodes can then be shorted (stuck) at normal welding amperage for about 2 seconds without theflux popping off, the coating can be considered sound.

11-5.8.1.4 The integrity of wet welding electrodes can be extended by pressurizing the electrodes in a sealed canister at the surface. The canister then can be vented at depth to equalize the pressure prior to removal of the electrodes.

11-5.8.2 Dry Chamber Welding Electrodes. The following welding electrodes are approved for repair of Naval ships based on qualification testing conducted under the direction of NAVSEA.

a. For ordinary and higher strength steels of MIL-S-22698: 1/8-inch E7018-M electrodes of MIL-E-22200/10.

b. For HY-80 and HSLA-80 modified steels: 1/8-inch E10018-M1 electrodes of MIL-E-22200/10. Any welding on the HY-80/HSLA-80 steels requires NAVSEA approval on a case-by-case basis.

c. Dry chamber welding electrodes must always be transferred to the dry chamber in a sealed container. This is part of the welding procedure qualification described in section 6.

11-5.8.2.1 Since these electrodes are of the low-hydrogen type, they must be handled as required in MIL-STD-1689. This means that electrode heating or baking ovens must be available whenever the electrodes will be exposed to the atmosphere for an extended period of time.

SECTION 6 - PROCEDURE AND PERFORMANCE QUALIFICATION

11-6.1 GENERAL.

Before any wet or UWDC welding can be performed on U.S. Navy ships or submarines, the underwater welding procedures shall undergo qualification testing; all nondestructive and destructive test results must be approved by NAVSEA prior to application of the underwater welding procedure. In addition, prior to application of the underwater welding procedure, all welder-divers must perform qualification testing using that procedure; in other words, each welder-diver must be qualified to use each procedure he is to use during production underwater welding applications. After performance qualification, each welder-diver is required to perform a confirmation weld at the job site prior to commencing production welding.

11-6.1.1 The following are a few of the items that are established or verified through welding procedure qualification testing:

a. Compatibility between the base metal and weld metal in terms of:

(1) Strength

(2) Ductility (the ability to stretch or bend)

(3) Toughness (resistance to fracture upon sudden impact or shock)

(4) Chemistry

(5) Metallurgical structure (internal structural configuration of the metals)

(6) Capability of being fused together by the welding process

b. The capability of successful welding under the environmental conditions imposed.

c. The adequacy of the intended weld joint design.

d. Applicability to the particular base metal thicknesses involved.

e. Filler metal handling requirements.

f. Adequacy of welding variables such as amperage, voltage, and travel speed.

11-6.1.2 Welding personnel qualification establishes or verifies the ability of the welder-diver to successfully use the qualified procedure:

a. Within the established welding variables

b. Under the imposed environmental conditions

c. In the required positions of welding.

11-6.1.3 The confirmation weld establishes or verifies the ability of the welder-diver to perform the required production welding under the actual conditions at the job site; it also verifies that the original welder-diver qualification has been maintained in such a way that his ability to perform successful underwater welding has not diminished.

11-6.2 WELDING PROCEDURE QUALIFICATION.

Welding procedure qualification shall be carried out as required in section 6 of NSTM Chapter 074, Volume 1, which establishes the basic procedure qualification and approval requirements; detail qualification requirements are established in the documents specified below, as invoked and modified by NSTM Chapter 074.

a. For UWDC welding, MIL-STD-1689 and NAVSEA S9074-AQ-GIB-010/248, Requirements for Welding and Brazing Procedure and Performance Qualification.

b. For wet welding, ANSI/AWS D3.6

11-6.2.1 Prior to beginning procedure qualification testing, a preliminary welding procedure (or welding procedure specification, WPS) is prepared. This welding procedure covers all the important welding variables, or essential variables, required for successful welding. Welding procedure qualification testing is then performed. Changes to the essential variables are made as necessary. After satisfactory completion of the qualification testing and establishment of final essential variables, any change in these variables — beyond specification allowances — requires requalification of the procedure. As required by section 6 of NSTM Chapter 074, Volume 1, a NAVSEA approved, independent third-party activity shall be obtained to witness all welding procedure qualification work.

11-6.2.2 UWDC Welding Procedure Qualification. NSTM Chapter 074 requires groove plate (butt weld) qualification in the vertical and overhead positions, which qualifies the procedure for groove and fillet welding in all welding positions. Typical essential variables are shown in Table 11-2. A typical welding procedure, used during previous Naval ship UWDC welding repairs, is shown in Appendix C.

11-6.2.3 Wet Welding Procedure Qualification. For carbon steel base metals and filler metals, NSTM Chapter 074 requires groove plate (butt weld) qualification in the flat, horizontal, vertical, and overhead positions using both 1/8-inch and 3/4-inch base metals. This qualifies the procedure for all position plate and tubular welding on base metal thicknesses from 1/8 inch through 1 1/8 inch. Qualification and use of austenitic stainless steel electrodes is limited to fillet welds only. Qualification and use of high-nickel electrodes shall be as approved by NAVSEA.

11-6.2.3.1 Typical essential variables are shown in Table 11-3. A typical wet welding procedure, used during previous Naval ship wet welding repairs, is shown in Appendix C.

NOTEDuring wet welding procedure qualification, choose the

welding current polarity that produces the best results. DCEN is preferred because of increased stinger life with this

polarity. However, some electrodes (such as the high-nickel type) may not perform well with DCEN.

11-6.3 WELDING PERFORMANCE QUALIFICATION.

Welder-divers shall undergo qualification testing to the requirements of section 6 of NSTM Chapter 074, Volume 1, and the applicable reference documents as specified in 11-6.2 above. Once the welding procedure has been qualified and approved, welder-divers can be qualified to that procedure.

11-6.3.1 As with procedure qualification, there are certain essential variables that are established during welder-diver underwater welding qualification. If any of these variables changes, requalification of the welder-diver is required. Appendix Dspecifies a recommended approach for welder-diver training in preparation for qualification testing.

11-6.3.1.1 UWDC Welding Performance Qualification. As specified in NAVSEA S9074-AQ-GIB-010/248, all-position groove and fillet weld qualification, for both plate and tubulars, can be accomplished by either of the following methods:

a. Groove (butt) weld plate welding in the hor-izontal, vertical, and overhead positions.

b. Pipe groove (butt) welding with the pipe in the vertical and horizontal positions.

11-6.3.1.1.1. Typical essential variables are shown in Table 11-4.

NOTEA UWDC welding procedure, and personnel qualified to that

procedure may be considered qualified to perform surface welding — provided the procedure and performance

qualifications satisfy all the essential variables of the surface welding application.

11-6.3.1.2 Wet Welding Performance Qualification. All-position groove and fillet weld qualification, for both plate and tubulars, can be accomplished by either of the following methods:

a. Groove (butt) weld plate welding in the horizontal, vertical, and overhead positions.

b. Groove (butt) weld pipe welding with the pipe in the 45 degree position.

11-6.3.1.2.1. Typical essential variables are shown in Table 11-5.

11-6.4 WELDING POSITION LIMITATIONS.

For purposes of wet welding procedure and personnel qualification, only limited movement of the test assembly is allowed. A maximum of 15 degrees tilt or rotation from the true (flat, horizontal, vertical, overhead) position is allowed.

11-6.5 MAINTENANCE OF PERFORMANCE QUALIFICATION.

A welder-diver can maintain his qualification as long as he uses the applicable welding procedure at least once every 3 months in production underwater welding. He can also maintain his qualification by performing a fillet weld test once every 3 months using the applicable applicable welding procedure; for UWDC welding, this can be done in the shop. A welder-diver loses his qualification in a specific procedure if he has not welded with that procedure for 6 months or more. Detail requirements for maintenance of performance qualification are specified in section 6 of NSTM Chapter 074, Volume 1.

11-6.6 CONFIRMATION WELD.

Each welder-diver must perform a confirmation weld test for each production welding job. This consists of making fillet break specimens in the vertical and overhead positions at the depth and location where the production repair weld will be made. Detail requirements for confirmation welding are specified in section 6 of NSTM Chapter 074, Volume 1.

SECTION 7 - REPAIR PROJECT PLANNING

11-7.1 INITIAL PLANNING.

The following steps should be taken during the initial planning for a Naval ship underwater weld repair project.

a. Determine the repair classification in accordance with section 4.

b. Whenever practical, determine the scope and extent of the repair work in advance.

c. Determine the type of equipment required for the repair.

d. Determine the type and number of personnel required for the repair.

e. Obtain standards, specifications and drawings applicable to the repair.

f. Obtain records or other information concerning unscheduled or emergency repairs that might impact the work to be done.

g. Coordinate the planned repair effort with the NAVSEA-approved third-party monitoring and certification activity.

11-7.2 UNDERWATER WELDING REPAIR WORK PACKAGE.

A repair work package shall be developed outlining ship identification, work to be performed, methods and procedures to be followed, records to be maintained, and approvals required.

CAUTIONEnsure that all tools and materials brought to the underwater job site are accounted for and removed at the completion of the job. Tools and material inadvertently left at the job site can generate unacceptable noise and possibly cause severe damage to shipboard components. Locally generated work packages shall ensure that a general tool and material log

sheet is prepared and maintained during all UWSH operations.

11-7.2.1 Specific consideration shall be given to the following in development of the work package:

a. Environmental factors such as water temperature and water clarity.

b. Availability of support services such as medical facilities, nondestructive testing services, and auxiliary power.

c. Actual thickness of material to be welded (which may not be as shown on ship’s drawings).

d. Carbon equivalent, based on chemical analysis performed on sample taken at job site, for wet welding projects.

e. Qualification status of welder-diver personnel.

11-7.2.2 Description of Work. An accurate, concise description of the work shall be specified. This shall be followed by a detailed description of the work to include the following:

a. Underwater survey of the repair area.

b. Development of dimensions and fabrication requirements for structural base metal to be incorporated in the repair.

c. Listing of any shipboard systems that must be shut down during the repair, with tag-out procedures.

d. Weld joint designs required and method(s) of joint preparation.

e. Listing of applicable welding procedures.

f. Specification by stock number or brand name of all welding and burning consumables to be used.

g. Listing of welder-diver personnel qualified to perform the welding.

h. Step-by-step description of the work to be performed.

i. A listing of all appropriate reference documents and their application to specific phases of the job.

j. Dry chamber design and fabrication requirements for UWDC welding.

k. Procedures for determination of base metal carbon equivalent for wet welding applications.

l. Any special requirements for maintaining environmental conditions at the work site.

m. Required nondestructive testing and acceptance criteria as specified in section 6 of NSTM Chapter 074, Volume 1.

n. Confirmation welding requirements.

o. Requirement that all repaired areas shall be painted with an approved underwater paint for corrosion protection.

11-7.2.2.1 Personnel or organizations should be assigned to all work listed above.

11-7.2.3 Records. The work package shall contain the necessary forms to ensure that the record keeping requirements of section 6 of NSTM Chapter 074, Volume 1, and MIL-STD-1689, section 5 are met. Certification of all welds requiring NDT in addition to VT within the scope of this chapter shall be documented on the QA Weld Joint Record. Work instructions may provide a sign off appendix for weld inspection records in lieu of the QA Weld Joint Record.

11-7.2.4 Approval. The work package shall be approved by the local Navy authority.

11-7.3 JOB COORDINATION.

It is the responsibility of the repair activity to coordinate all efforts with supporting activities to ensure the safety and efficiency of the operation. Persons and activities with whom contact must be maintained may include, but are not limited to,emergency medical facilities, shipboard personnel, the harbor master, government and commercial technical representatives and advisors, and the third-party verification agency.

11-7.4 JOB DOCUMENTATION.

At the completion of the job, the approved job package shall be forwarded to NAVSEA. Detailed documentation of the damage assessment and any unique problems encountered and their resolution shall accompany the work package. A written report should also be provided to the Chief Engineer of the ship for the ship’s records. A copy shall also be kept by the repairing activity. This report shall contain all information pertaining to the repair including photographs, all QA documents, and any post repair action required (e.g., periodic inspections, rework during next scheduled dry-docking etc.).

SECTION 8 - WELDING TECHNIQUES

11-8.1 GENERAL.

This section is directed primarily toward wet welding. The U.S. Navy Underwater Cutting and Welding Manual provides a handy reference for specific techniques and methods that have been shown effective in wet welding. It is not intended to repeat this information herein. This section presents additional information regarding wet welding techniques that should assist thewelder-diver in better understanding just what is involved in producing satisfactory wet welds. It should be noted that this section varies from the information presented in the U.S. Navy Underwater Cutting and Welding Manual with respect to the following:

a. Integrity of wet welds deposited using the self-consuming technique as compared to the manipulative technique.

b. The degree of bead overlap required for wet welds.

11-8.1.1 The welding techniques required for UWDC welding are basically the same as those required for welding topside for the water depths covered by this document, and details of these techniques are not addressed herein. It should simply be considered that the UWDC welding arc is somewhat constricted by ambient pressure which may place some additional limitation on puddle size and the amount of metal that can be carried in a weld pass.

11-8.2 PUDDLE CHARACTERISTICS AND WELD DISCONTINUITIES.

The environment during wet welding produces some unusual conditions and results. For example:

a. Bubbles produced by the welding can block the welder-diver’s vision.

b. Water current can affect the welder-diver’s stability or cause an unstable welding arc.

c. Fast quenching of the molten weld metal produces porosity resulting from gases that do not escape the puddle prior to its solidification.

d. Unequal pressures acting on the arc can require compensation in welding technique as the bead progresses.

e. Excess hydrogen and oxygen, from dissociation of the steam in the arc atmosphere, reduce toughness of the weld metal and increase the chances for porosity.

f. Proper body position, with respect to visibility and control of the welding electrode, can be difficult to achieve.

g. Cold water, in conjunction with limited body movement during welding, can decrease the welder-diver’s effective welding time.

h. The window for satisfactory welding, in terms of amperage, voltage, and travel speed, is smaller than that for topside welding.

i. As water depth increases, increased ambient pressure magnifies some of the above effects.

11-8.2.1 All the above situations can influence the weld puddle and thus impact the potential for weld discontinuities (rejectable discontinuities are known as weld defects). However, this influence can be minimized by the use of welding procedures and properly trained personnel qualified to the requirements of section 6 of NSTM Chapter 074, Volume 1.

11-8.2.2 Observance of the following principles, and the techniques and methods outlined in the U.S. Navy Underwater Cutting and Welding Manual, should assist the welder-diver in his training toward qualification for wet welding.

a. Positioning of the body must always be such that bubbles from welding do not interfere with vision of the weld puddle.

b. Where possible, both hands should be used: one hand holding the stinger and the other guiding the electrode.

c. The stringer bead or drag technique produces less porosity and a higher quality weld than a weave or manipulation technique; weaving or manipulation should only be used where necessary to control the puddle or to bridge a gap. Any weave or manipulation usually results in a longer arc (with higher arc voltage). This leads to more weld spatter, more hydrogen and

oxygen being sucked into the arc plasma, and a higher quench rate for the molten metal. (Higher quench rates increase the strength and hardness while reducing the ductility and toughness.)

d. Where water current is strong enough to move a welding lead, the lead should be tied off as close to the welding as practicalto prevent its affecting the stability of the welding stinger. However, if the water current is this strong at the welding depth, it will probably interfere with arc stability by removing the protective bubble around the arc. Water currents approximately 1 knot and higher can create such problems.

e. Perform occasional checks on the ground connection to ensure the soundness of the connection. If welding problems occur, this should be the first check made. Arc blow due to magnetic fields seems more common in wet welding than welding topside; therefore, proper location of the ground connection(s) can be critical.

f. Always have a sufficient quantity of welding lens shades (numbers) to ensure adequate visibility for the water condition. Although much of the welding technique depends on feel, quality welds can not be made when the weld puddle is not visible.

g. The integrity of the electrode waterproof coating is critical. Where flux pops or explodes off the core wire during welding, it can be concluded that water is penetrating past the waterproofing into the flux, causing a steam buildup that blows the flux away.

h. Adjacent weld beads should overlap about 50 percent to avoid deep valleys which can lead to excessive grinding.

i. Weld residual stresses (or shrinkage stresses) associated with wet welding are very high. Where grinding reduces the thickness of certain types of weld passes too much, the residual stresses can cause the weld bead to crack; unless the crack is detected and ground out, the crack can follow the subsequent weld beads all the way to the weld cap. Weld root passes tying two members together, and any weld pass that bridges a gap, are susceptible to cracking due to excessive grinding.

j. Always verify the chemistry of the base metal being welded to ensure its weldability, as addressed in section 4.

k. It is wise to occasionally verify that the welding polarity is as required in the welding procedure (the heavier stream of bubbles always comes off the negative pole of the welding circuit).

l. When depositing root passes, especially in joints where the sides intersect at an angle of 90 degrees or less, a heavier rod pressure is required to obtain adequate penetration.

11-8.3 POSITIONS OF WELDING.

Welding positions for pipe and plate are defined and discussed in ANSI/AWS D3.6. The four basic positions of welding are flat (F), horizontal (H), vertical (V) and overhead (OH); certain limitations for these positions are described in 11-6.4. The U.S. Navy Underwater Cutting and Welding Manual addresses fillet welding techniques for the H, V, and OH positions.

11-8.3.1 Specific welding techniques for the various positions depend on the water depth, capability of the welder-diver, type of electrode, and welding parameters such as amperage, voltage, and travel speed. In other words, welding technique will depend on the specific conditions and personnel capabilities at the work site. Additional information regarding specific positions is provided below. This information is intended to offer the welder-diver some insight regarding the positions of welding to better prepare him in developing the necessary techniques for successful wet welding.

a. Flat. This is normally considered the easiest position of welding. However, the bubbles generated at the arc in wet welding require the welder-diver to move to a position that does not allow him optimum visibility and control. The flat position allows the gases to escape the weld area without hindrance; this should result in reduced weld metal porosity.

b. Horizontal. Visibility in this position should be good where the welder-diver can get his head low enough to keep the bubbles from interfering with his vision. As with topside welding, the beads will have some sag in the H position; this requiressome degree of planning for proper bead sequence. As with F position welding, gases can escape the weld area fairly easily, which should minimize porosity problems.

c. Vertical. Travel speed is critical in this position. As with other positions, if the speed is too fast, there will be inadequate penetration and possibly inadequate weld deposit. On the other hand, the travel speed must be fast enough to keep the molten metal, or the slag, from running ahead of the arc. Therefore, the window of operating parameters is smaller for this positionthan for the other positions.

(1) Welding progression in the V position is usually in the downward direction; this allows the bubbles to escape behind the leading edge of the puddle allowing better visibility of the welding. However, the gases are moving back against the puddle,

which can result in more weld metal porosity. Although welding progression can be upward, this requires a great deal more skill, and most wet welding electrodes do not perform well using this technique.

(2) Due to the fast travel speed required in the V position, the heat input is lower and results in a higher weld cooling rate. This produces higher hardnesses in the weld and the base metal heat-affected zone. Heavy rod pressure is considered important when depositing root passes in the V position to obtain adequate penetration.

d. Overhead. This is usually considered the most difficult welding position due to the awkward position of the body and visibility problems caused by bubbles. However, practice and experience allow the welder-diver to develop the necessary methods required to produce sound welds in this position. Proper positioning of the body is more important for the OH position than for any other welding position.

(1) Since the bubble protection at the arc is greater than with the other welding positions, the weld is closer to a UWDC weld in terms of heat input; this increases penetration and reduces hardness. The slower cooling can also result in less porosity.

11-8.4 COMMON WET WELDING PROBLEMS.

See 11-10.2 for a discussion of common welding problems and their probable causes.

WARNINGDuring wet welding, bubbles rising to the surface carry

explosive gases such as oxygen and hydrogen. They can also carry small particles of glowing slag. Care shall be taken to

ensure that there are no voids (i.e., sea chest openings) above the welding where the rising bubbles can displace the water

and thus cause an explosion.

11-8.5 ARC BLOW AND MAGNETIC FIELDS.

Arc blow is caused by magnetic fields acting on the arc (since the arc is an electric field, it can be affected by magnetic fields). Magnetic fields can occur any time the electric current suddenly changes direction, for example, at the edge of a plate or plate bevel. Wet welding seems to be more influenced by magnetic fields than dry welding. For example, when wet welding on a flat carbon steel plate, a magnetic field begins to build up at the plate end toward which the arc is traveling. As the number of weld passes increase, the magnetic field becomes stronger — such that the arc begins to experience the effects of the magnetic field further away from the end of the plate. As the carbon steel’s strength and alloy content increase, so does its ability to retain magnetic fields; in some steels, this results in a field buildup at the top of a groove weld bevel, causing arc blow as the precapping passes are applied.

11-8.5.1 Magnetic fields can also be introduced by excessive grinding on hard steel, especially when the grinding takes place at the faying surfaces where two plates come together, such as at the root of a backing bar groove weld. In some cases, a magnetic field introduced by disc grinding can be eliminated using a burr grinder (grinding perpendicular to the original grinding).

11-8.5.2 Sharp discontinuities in a weld, such as cracks, can also produce magnetic fields. When located close to the surface of the weld, these fields can cause arc blow.

11-8.5.3 Elimination of magnetic fields, as well as development of these fields, is fairly complex. Where the object being welded is small, beating with a hammer can reduce the fields. Where the welding leads can be wrapped around the object, in close proximity to the weld, magnetic fields can be reduced if the current flowing through the leads is in the proper direction (if the current is in the wrong direction, the strength of the field will be increased).

11-8.5.4 Proper location of the ground lead connection has a significant effect on the development of magnetic fields. In some cases, welding toward the ground connection produces better results; in other situations, welding away from the ground connection works better. In other cases, splitting the ground lead to obtain two ground connections works best. A good rule of thumb is to locate the ground such that there is a minimum number of “corners” for the welding current to “turn” in its path between the electrode and the ground connection.

SECTION 9 - INSPECTION OF WELDMENTS

11-9.1 GENERAL.

For the welding governed by this document, there are five basic inspection (nondestructive testing) methods. These methods are:

a. Visual

b. Liquid penetrant

c. Magnetic particle

d. Radiographic

e. Ultrasonic

f. Eddy Current

11-9.1.1 Each of the above inspection methods has unique capabilities for the detection of specific types of weld discontinuities, and their application depends on accessibility at the weld and the discontinuity of interest. NSTM Chapter 074, Volume 1, governs the method of inspection and acceptance standards required for underwater welding covered by this document. Application techniques are covered by MIL-STD-271, and detailed acceptance standards are contained in MIL-STD-2035.

11-9.2 VISUAL TESTING (VT).

Visual inspection is performed on completed weld beads and is done throughout the welding operation. The official visual inspection, however, is usually accomplished at the completion of the weld (sometimes an official inspection is required after completion of the root layer). Items of interest during visual inspection are surface porosity, weld contour and reinforcement height, undercut, bead overlap, and bead tie-in.

11-9.3 LIQUID PENETRANT TESTING (PT).

This inspection method is used to detect weld surface discontinuities. It uses a colored penetrating liquid which is sprayed on the weldment and allowed to seep into any discontinuities open to the weld surface. After a few minutes, the excess penetrantis wiped away and a developer is sprayed on the weld surface. The powdery developer then draws out penetrant from the discontinuities, showing colored indications in the shape of the discontinuities. Liquid penetrant inspection can be used for all types of metals, but it is normally used on nonferrous metals and metals that cannot be magnetized.

11-9.3.1 Obviously, liquid penetrant inspection can not be used in the wet, so its use is limited to UWDC welding and wet test welds that can be brought to the surface for examination. Since oil-based compounds are often used for penetrants, and since solvents are necessary during wiping and cleaning the penetrants, this inspection method must be used cautiously in a dry chamber.

WARNINGMaterials used with liquid penetrant inspection are flammable

and must be used with caution in a dry chamber.

11-9.4 MAGNETIC PARTICLE TESTING (MT).

This inspection method is used to detect linear weld surface discontinuities such as cracks in metals which can be magnetized. For work governed by this document, inspection is carried out using permanent magnets, yokes, or prods. Yokes and prods use electrical current to produce a magnetic field; yokes use alternating current, whereas prods use either alternating or directcurrent. In all cases, a magnetic field is established in the weld between the two contact points of the inspection device. When the field intersects a sharp discontinuity in the weld, metal particles are attracted to the site; the formation of the metal particles follows the outline of the discontinuity. Most significant discontinuities will hold the particles in place after the magnetizing force has been removed.

11-9.4.1 Direct current prod is usually the more sensitive method, except that AC yoke is generally more sensitive to shallow surface indications. The final choice of MT inspection technique depends on the configuration of the structure to be inspected. MT can be performed either in the wet or in the dry.

11-9.5 RADIOGRAPHIC TESTING (RT).

This inspection method uses rays from radioactive sources to detect both surface and subsurface weld discontinuities. The rays pass through the weld from one side to form images on film located on the opposite side. Weld discontinuities that are less dense than the weld metal (slag, porosity, cracks) show up as dark images; discontinuities that are more dense than the weld metal show up as light images (other than weld spatter, these discontinuities should not occur with shielded metal arc welding).

11-9.5.1 Radiographic sources are of two types. One type uses an electrically powered machine to generate X rays; this type of power source is usually stationary, such as that used in hospitals. The other source is a radioactive material, such as iridium, and generates gamma rays. This source is portable and is most often used in the field.

11-9.5.2 RT is capable of detecting all types of weld discontinuities. However, tight linear indications such as cracks and lack of fusion must be oriented such that their depth plane is parallel with the rays; otherwise, they will not show up, or they will not show up clearly.

11-9.6 ULTRASONIC TESTING (UT).

This inspection method uses high-frequency sound waves generated by a small, portable electronic unit. The sound waves are transmitted through a lead to a transducer unit; the technician slides the transducer along the weld, sending sound waves into the metal; the sound waves are reflected back through the transducer to give a readout on an oscilloscope. A couplant (such as water, glycerin, or grease) is used between the transducer and the weld to provide a transmission medium for the sound waves, since the waves will not cross an air barrier.

11-9.6.1 UT techniques of interest for this document are the compression wave and the shear wave techniques. With the compression wave technique, the sound waves move through the material perpendicular to its surface; this technique is generally used to check material thickness or to check for laminations in the material. With the shear wave technique, the waves move through the material at some predetermined angle; this technique is generally used to evaluate weldments.

11-9.6.2 The principles for both the compression and shear wave techniques are the same. The sound waves are reflected off discontinuities (or any surface where the metal ends and air begins, such as the backside or edges of the base metal or weld being inspected) for evaluation on the oscilloscope.

11-9.6.3 During the inspection of weldments, UT is used primarily for detection of linear discontinuities such as slag, nonfusion, and cracks that have enough height to provide an area large enough to reflect the impinging sound waves. Porosity indications, which are small and have rounded surfaces, are difficult to evaluate with UT. UT has the advantage of defining both the length and the depth of a weld discontinuity.

11-9.7 EDDY CURRENT TESTING (ET).

This inspection method is used to detect surface and subsurface cracks and seams. It is based on the principle that eddy currents are induced in metals whenever they are brought into an alternating current magnetic field. These eddy currents create a secondary magnetic field which opposes the inducing magnetic field. Discontinuities or material variations alter the eddy currents changing the apparent impedance of the inducing coil. Changes in impedance are detected by the sensor, amplified, and modified in order to activate audio or visual indicating devices.

11-9.8 LIMITATIONS.

The following are the primary limitations for the inspection methods covered herein.

a. Visual. VT is limited to surface inspection and to discontinuities that are large enough to be seen by the unaided eye. Fine line cracks can easily be missed by VT.

b. Liquid penetrant. PT is limited to surface inspection. It is time consuming and requires careful cleanup to avoid contamination of the surface such that subsequent welding or painting would be adversely affected.

c. Magnetic particle. MT is limited to surface inspection for linear indications.

d. Radiographic. RT is time consuming and requires removal of personnel from the area while the inspection is being performed. RT is generally used to inspect butt welds, as opposed to tee and corner welds. RT is fairly common in a dry chamber environment; it is seldom done in the wet.

e. Ultrasonic. UT is generally limited to linear or “planar” type indications; however, shallow surface cracks can be difficult to evaluate due to “scatter” of the sound waves near the surface. The capability of UT is highly dependent on the capability of the UT inspector and his ability to interpret the oscilloscope readout.

f. Eddy current. ET is generally limited to detection of surface cracks in welds due to the shallow depth of penetration. It is also sensitive to variations in material content and part geometry. Operation of this component requires the use of reference standards for calibration.

11-9.9 GENERAL APPLICATION.

The above inspection methods can be considered appropriate for application as shown in the table below.

Joint Type Inspection Method

Tee weld, fillet VT, MT, PT, ET

Tee weld, groove VT, MT, PT, UT, ET

Corner weld, fillet VT, MT, PT, ET

Corner weld, groove VT, MT, PT, UT, ET

Lap weld (fillet) VT, MT, PT, ET

Butt weld VT, MT, PT, RT, UT, ET

SECTION 10 TROUBLESHOOTING

11-10.1 INTRODUCTION.

During a typical underwater welding project, there can be two primary sources of trouble:

a. Inadequate preliminary planning and investigation

b. Improper welding technique

11-10.1.1 When preliminary planning and investigation is not accomplished properly, there can be all sorts of problems —such as those associated with equipment, personnel training and qualification, environmental conditions, base metal chemistry, and base metal thickness. In these situations, welding technique may not be a significant factor in the problems incurred.

11-10.1.2 It is essential that the performing activity take the necessary steps to ensure that the principles outlined in section 7have been implemented, which should result in the following:

a. Filler metal application is in accordance with section 4.

b. Third-party evaluation and NAVSEA approval are as required by section 4.

c. Equipment is selected and maintained as required by section 5.

d. Underwater welding procedures and personnel are qualified in accordance with section 6.

11-10.1.3 Assuming the above has been accomplished, this section is aimed at troubleshooting specific problems associated with both the welding process and the weld quality.

11-10.2 COMMON WELDING PROCESS PROBLEMS.

An incorrect electrode lead angle can cause all the problems shown below. Other potential causes are as shown in Table 11-6below.

11-10.3 COMMON WELDING QUALITY PROBLEMS.

Weld quality problems and their potential causes are shown in Table 11-7 below. Although this information was developed with wet welding in mind, it is also applicable to UWDC welding. As with the welding process, incorrect electrode lead angle can also cause these problems.

11-10.4 ARC BLOW AND MAGNETIC FIELDS.

See 11-8.5.

11-10.5 BASE METAL CRACKING WITH RESPECT TO ELECTRODE TYPE.

See 11-4.1.2.

11-10.6 POWER SUPPLY PROBLEMS.

See 11-5.3.

11-10.7 ELECTRICAL CIRCUIT PROBLEMS.

See 11-5.4.

11-10.8 ADDITIONAL CONSIDERATIONS.

The following describes additional situations that may interfere with underwater welding operations.

11-10.8.1. Cathodic Protection Systems. Impressed current and sacrificial anode cathodic protection systems can generate electric fields which can interfere with arc stability if the underwater welding is close enough to these systems. The performing activity should always check to see if such systems are in operation. Their proximity to the underwater welding should be evaluated. In most cases, however, arc instability problems are more likely to be a result of other factors previously covered herein.

11-10.8.2. Geographic Variations In Magnetic Fields. Changes in the earth’s magnetic fields, as the geographic location changes, are fairly common. Polarization of structures, within the earth’s magnetic field, is also quite common. As a result, welding current polarity can be affected during wet welding. Therefore — though it is the exception rather than the rule — one welding polarity may produce better results for one job, and the other polarity may produce better results on another job. Although it may be impractical, the ideal situation is to have welding procedures qualified using both DCEP and DCEN polarities (see 11-6.2.1).

11-10.9 TROUBLESHOOTING SUMMARY.

It must be emphasized that the majority of the above problems should not occur during production welding operations. Most of the problems should have been solved during underwater welding training and qualification. The above information is presented to aid the welder-divers in successfully qualifying for production work while alerting them to potential problems resulting from peculiar conditions at the job site.

SECTION 11 - UNDERWATER WELDING WORKMANSHIP

11-11.1 GENERAL.

This section specifies the minimum requirements for visual and dimensional inspection of underwater dry chamber and wet welds from fit-up through final acceptance for the workmanship requirements of NSTM 074 Volume 1 and MIL-STD-1689.

11-11.2 VISUAL INSPECTION.

Visual inspection of all new or repaired welds, removal sites, and temporary welds is required by personnel qualified to thissection. Documentation of visual inspection is required for those welds for which other NDT (ET, MT, PT, RT, UT) is required.

11-11.2.1 Unless otherwise specified herein, visual inspection need not be performed employing magnification. When magnification, such as borescope or magnifying glass is employed for convenience, evaluation and acceptance shall be based upon comparison with the appearance of a “standard” where both unmagnified and magnified surface appearance can be determined and compared.

11-11.2.2 Visual inspection of dimensional characteristics shall be performed using templates, gages, micrometers, or other measuring devices. NAVSEA approved workmanship samples may be used for evaluation when gages cannot be used due to space limitations or joint configuration.

11-11.3 VISUAL INSPECTION STANDARDS.

Visual inspection standards refer to devices which may be used as aids to visual and dimensional inspection of welds and weldments. Visual inspection standards, such as workmanship samples, sketches, or photographs shall be approved by NAVSEA.

11-11.3.1 Visual inspection shall be performed with adequate lighting. Adequate lighting is defined as a minimum of 50-foot candles. A standard two-cell flashlight with good batteries provides approximately 100 candles at a distance of one foot.

11-11.3.2 Acceptance inspection of all completed welds shall be performed on welds in the final surface condition. Final surface condition is the condition of the weld surface after all the surface finishing operations have been completed, (e.g.,grinding, machining).

11-11.3.3 Inspection and measurement of fillet and fillet-reinforced welds shall include measurement of welds with scales, gages, etc., in enough areas to verify that minimum fillet leg and throat thickness requirements are met for the entire weld.Each leg shall be measured with an approved gage as shown in Figures 11-4 and 11-5. Weld sizes specified on drawings for equal leg (1x1) fillet or fillet reinforced welds are designed to provide a minimum throat thickness of 0.7T (0.7 x the specified leg length) or greater. Throat thickness for (2x1) fillets is designed to be 0.9T. Throat thickness is the shortest distance from the face of the weld to the root of the weld.

11-11.3.4 Fillet and fillet reinforcement welds shall be essentially flat (-1/16 inch to +3/16 inch of a line drawn toe to toe). Throat thickness shall be measured for concave fillets (welds less than flat) and shall equal (touch) or exceed the minimum size throat gage (or other suitable gage, inch scale or template) as shown in Figure 11-4.

CAUTIONJust measuring the largest fillet leg and not measuring the

smaller leg gives a false indication of the fillet size. The shortest leg length is used to determine the actual fillet weld

size.

11-11.3.5 Examples of measurement of each fillet leg for fillet and fillet-reinforced welds is shown in Figure 11-5 for welds with angles of 90 ± 15°. Each weld leg length shall equal (touch) or exceed the appropriate weld gage.

11-11.3.6 Fillet and fillet-reinforced attachment welds with angles greater than 105° shall have leg lengths increased as indicated in Table 11-8. The leg length of welds for angles less than 75° shall be the size indicated in Table 11-8 or specified on the drawing. For weld sizes or angles not covered by Table 11-8, contact NAVSEA. A fillet tee weld example with angles greater than 105° and less than 75° is shown in Figure 11-6.

11-11.3.7 Suitable gages as shown in Figure 11-7 shall be used to measure weld reinforcement, undercut, and depressions in welds or base materials.

11-11.4 SURFACE FINISH AND CONTOUR.

Verification and satisfactory surface finish and weld contour is required for all welds and adjacent base material. Questionable surface finish and contour shall be compared to workmanship samples.

11-11.4.1 For in-process welds, the surface shall be suitable for subsequent welding. In general, as-welded surfaces are acceptable provided there are no sharp surface irregularities between weld beads and the surface finish and contour are compatible with the required nondestructive testing (e.g., PT, UT, MT, RT, and ET) to be accomplished.

11-11.4.2 For completed welds, the weld contour shall blend smoothly into the base metal. The completed weld and a minimum of 1 inch (where possible) of the adjacent base material surfaces on each side of the weld fusion line (weld toes) shall be clean, free of all foreign material and smooth, excluding acceptable undercut or acceptable weld spatter for welds only VT inspected. Additional cleaning is required if the joints are to be PT or MT inspected after welding, i.e., adjacent base material should be clean 1 1/2 inches from each weld fusion line.

11-11.5 REPAIR OF WELD DEFECTS.

Weld defects, defined herein as unacceptable and detected by visual test (VT), shall be removed and/or repaired to the extent necessary to render the area acceptable.

11-11.6 VERIFICATION SIGNATURE.

When a verification signature is required for fit-up, the verification signature should not be made until the joint is held in place by either a fixture or tack welds (i.e., joint fit-up tolerances and alignment are fixed and can not change). A qualified workmanship inspector verifies with a single signature that applicable requirements have been met for joint fit-up. If all fit-up attributes are not verified by one workmanship inspector, each person shall sign for the workmanship they verified.

11-11.7 TRAINING/SKILLS

VT Inspection Examiners shall be trained and certified in accordance with UWSH Manual chapter 7.

11-11.7.1 Personnel performing visual inspections shall be certified as visual inspectors, but fit-up inspections can be accomplished by personnel trained as Workmanship Inspectors.

11-11.7.2 Workmanship Inspectors shall be required to pass an annual vision test. The test shall be administered by a certified individual using standard test methods for determining visual acuity. Vision test acceptance standard shall be the ability to read standard Jaeger Type Chart J1 letters for near vision (or equivalent) with natural or corrected near distance vision. Glasses or other corrective aids used to pass the tests shall be used when performing production work.

11-11.7.3 Personnel performing visual workmanship inspections to the requirements of this instruction shall also be trained and qualified by an approved VT Inspection Examiner.

11-11.8 RECORDS.

Records shall be maintained for all personnel trained and certified as Visual Workmanship Inspectors. Records of training and certification shall be maintained by Visual Inspection Examiners for the current and preceding certification period. Workmanship Inspectors shall be recertified at least every 3 years. Examiners shall also ensure current eye test results and records of current and preceding maintenance of qualification (not to exceed 6 months) are available for review. Examiners shall ensure that a list of certified personnel is published at least monthly.

11-11.9 VISUAL INSPECTION AND ACCEPTANCE CRITERIA.

11-11.9.1 General. The following sections provide the visual and dimensional inspection requirements and acceptance criteria for all welding in accordance with MIL-STD-1689. These requirements are applicable to all surface ship welds and all submarine structure welds except for high-yield steels (i.e., HY-80, HY-100, and HY-130).

11-11.10 GENERAL VISUAL INSPECTION REQUIREMENTS.

Ensure that the correct underwater weld procedure is specified for welding and that the welder/diver is qualified and qualification has been maintained for the weld type and material to be welded. Ensure that the filler material is the correct type, size, and manufacturer required by the weld procedure.

11-11.11 VISUAL INSPECTION PRIOR TO WELDING.

11-11.11.1 Base Material. The base material shall be the type and quality level required by the assembly drawing and/or work instruction. Chemical analysis shall be performed on all base material to be wet welded for Carbon Equivalent determination. Base material shall be inspected to the following criteria:

a. The base material shall be free of arc weld metal spatter. Base material shall be free of arc strikes, grinding marks, nicks,gouges and other fabrication scars greater than 1/32 inch in depth. Surface roughness and handling marks greater than 1/32 inch in depth shall be repaired by grinding and fairing into adjacent material provided such grinding does not exceed the undercut limits of paragraph 6.6.

b. Surface ship base material laminations covered by welding shall not exceed:

(1) Individual laminations greater than 8 inches long in 24 inches of base material.

(2) Total accumulated lamination(s) length of 12 inches in 24 inches with no single lamination greater than 6 inches long.

c. Submarine base material laminations covered by welding shall not exceed:

(1) Individual laminations greater than 1/2 inch in length.

(2) Total accumulated lamination(s) length of 4 inches in 6 inches of base material.

d. Any unacceptable base material defects or laminations not covered by welding noted during fit-up inspection shall be reported to NAVSEA prior to welding.

11-11.11.2 The joint preparation shall be in accordance with referenced drawings and work instructions.

11-11.11.3 The weld prep and adjacent base metal surfaces shall be clean for a minimum of 1 inch (1 1/2 inches if PT is required) from the weld area as follows:

a. The area shall be free of paint, oil, grease, moisture (if dry chamber), scale, oxide, rust, zinc or galvanizing and surface defects that would interfere with welding or NDT.

b. Zinc coatings shall be removed, prior to welding, by blasting, grinding, or chemical means.

11-11.11.4 Plate edges shall be prepared for welding by one or a combination of the following methods:

a. Automatic oxy-fuel gouging

b. Carbon arc-air gouging

c. Chipping

d. Grinding or burring

e. Machining

f. Oxy-fuel gas cutting

g. Plasma arc cutting

11-11.11.5 The use of oxy-fuel gas gouging is prohibited for HY-80/100 or HY-130, quenched or tempered steels, and high hardenable materials (i.e., special treatment steel (STS) and steels with carbon content in excess of 0.30%.

11-11.11.6 Check for adequate clearance for welding. Be sure that snipes in adjacent structure are large enough to allow welding and accommodate the correct weld size (see Figures 11-8 and 11-9).

11-11.11.7 Prior to production welding, a confirmation weld test shall be performed in accordance with NSTM 074 Volume 1 section 6.

11-11.11.8 The weld build-up of joint preparations to correct oversize root openings, errors in joint preparation, for fairing, or for other correction over or adjacent to welds may be employed provided the below restrictions are not exceeded, and shall beconsidered part of the involved weld.

11-11.11.9 Weld build-up to correct oversize root openings shall meet the following:

a. The build-up must be completed prior to joint welding.

b. The build-up of each edge shall not exceed “T” or 1/2 inch, which ever is less, where “T” is the thickness of the thinner member being welded. Where one side of the joint is not accessible, the total build-up (2T or 1 inch) may be deposited on one member.

11-11.11.10 If approved by an appointed NAVSEA third party monitor, a temporary backing of a compatible metallic or other approved materials may be used in the joint root to allow welding across the excessive root opening, provided it is subsequently removed prior to completing the weld.

11-11.12 VISUAL INSPECTION OF FIT-UP.

11-11.12.1 Butt joint alignment shall be such that misalignment after welding shall not exceed the limits of Table 11-10. The plating shall be restrained, as required, to assist in maintaining alignment.

11-11.12.2 The root opening shall meet the requirements of the assembly drawing and work instructions. When the root opening of a fillet tee weld exceeds 1/16 inch, but is not more than 3/16 inch as a nominal condition, a line shall be scribed along the length of the joint indicating the minimum fillet size plus the additional root opening. Subsequent welding to the scribed line ensures that the weld size is increased by an amount equal to the excess root opening.

11-11.12.3 As a minimum, joint fit-up, completed root pass, preheat set-up and control (when required) shall be observed by video and photographed in accordance with NSTM 074, Volume 1, section 6.

11-11.12.4 The minimum dimension of an insert, patch, or small access plate in surface ship plating and structure other than pressure hull envelope shall be 4T or 3 inches, whichever is larger, where T is the thickness penetrated. Corners of inserts,patches, or small access plates in plating and structure other than the pressure hull envelope shall have a minimum radius as shown (see Figures 11-10, 11-11, and 11-12).

11-11.12.5 Inserts, patches, or small access plates shall not intersect any other full penetration butt welds unless they land on these welds or cross them at a 90° +/- 15° angle as shown in Figure 11-11. When the boundaries land on existing full penetration butt welds, the common length of weld shall not be less than 12 inches. When the boundaries do not land on existing full penetration butt welds, the toes of the weld of the insert, patch, or small access plate shall be a minimum of 3 inches from the toe of the weld of any other full penetration butt welds (1/2 inch from fillet welds) (see Figure 11-13), except for the following:

a. Circular inserts.

b. Circular patches.

c. Circular small access plates.

d. Penetrations.

11-11.12.6 When inserts, patches, or small access plate welds land on other full penetration butt joints, the existing weld shall be cut back a minimum distance of 3 inches.

11-11.13 VISUAL INSPECTION DURING WELDING.

11-11.13.1 Slag shall be removed before any nondestructive testing (e.g. VT, MT, PT, RT, ET, or UT) is performed.

11-11.13.2 Tack welds shall be made by using approved weld procedures and filler material quality level as required for the final weld. Tack welds shall be deposited so as to facilitate incorporation into the final weld. Cracked or poor quality tackwelds shall be removed; however, tack welds deposited on the backside of a weld joint need not be removed prior to welding the first side if the backside is to be backgouged.

11-11.13.3 Backgouge. The weld root reverse side shall be cleaned to sound metal and contoured to allow deposition of weld metal from the second side. The side wall shall slope, without sharp breaks or keyholing, with a bottom radius of 1/8-inch minimum. If keyholing resulting from grinding or gouging is present, additional metal shall be removed to permit proper electrode accessibility and manipulation (see Figure 11-14).

11-11.14 VISUAL INSPECTION AFTER WELD COMPLETION.

11-11.14.1 All welds performed in a dry chamber shall be MT or PT inspected, as applicable. This includes the backgouged root surface of full penetration groove welds. 5X visual inspection may be substituted for MT or PT backgouge inspection.

11-11.14.2 100% RT inspection shall be performed on full penetration dry chamber butt welds in primary structure that are 1/4 inch thick and over. If accessibility precludes RT, UT inspection may be substituted. Where RT or UT cannot be performed, MT of each weld layer may be accomplished when approved by NAVSEA.

11-11.14.3 All underwater welds (including root layer and final welds) shall be VT inspected and photographed.

11-11.14.4 The weld size shall be as required by the assembly drawing, work instructions, and the following:

a. Butt welded joints shall not be less than flush with the plate surface, except for acceptable weld and grind undercut.

b. The weld reinforcement on “hydrodynamic” surfaces shall not exceed 1/16 inch. The weld reinforcement on other surfaces shall not exceed:

(1) Up to and including 1/2-inch base material thickness: maximum reinforcement of 3/32 inch

(2) Over 1/2-inch base material thickness: maximum reinforcement of 5/32 inch.

c. Fillet welds shall meet the minimum dimensional fillet size requirements of the work instruction and/or assembly drawing.

d. Fillet tee welds shall be inspected to ensure that the scribe line applied in accordance with paragraph 11-11.12.2 is not visible after welding.

11-11.14.5 The contour of the completed weld shall be free of sharp irregularities between beads and shall fair into the base material at the weld edges with a re-entrant angle of 90 degrees or greater.

11-11.14.6 Grind Undercut. When grinding is used to effect repairs for correction of weld-edge condition, grind undercut shall blend smoothly into the base material with no sharp irregularities. Grind undercut shall be measured from the undisturbed base material surface and shall not exceed a depth specified or reduce plate thickness as noted below:

a. To a depth of 3/32 inch or 15 percent below design thickness, whichever is less, for a maximum length of 12 inches in any 36-inch length of weld.

b. To a depth of 1/16 inch or 15 percent below design thickness, whichever is less, for any length in excess of a. above.

11-11.14.7 Weld undercut shall blend smoothly into the base material with no sharp irregularities.

a. Base material less than 1/2-inch thickness:

The maximum weld undercut without repair shall be 1/32 inch or 10 percent of the adjacent base material thickness, whichever is less.

b. Base material thickness 1/2 inch and greater:

Undercut up to 1/16 inch is allowed for 15 percent of the joint length or for a maximum of 12 inches in any 36-inch length of weld, whichever is less. Undercut of 1/32 inch is allowed for the entire joint length.

c. Weld undercut and other weld edge defects may be repaired by grinding provided such grinding does not exceed the limits for grind undercut.

11-11.14.8 Butt plating alignment shall be within the limitations listed below:

11-11.14.9 Surface Condition.

The weld and base material shall be free of visible arc strikes and weld spatter. The base material shall also be free of grinding marks, nicks, gouges and other fabrication scars greater than 1/32 inch in depth. Surface roughness and handling marks greater than 1/32 inch in depth shall be contour ground and meet the grind undercut and contour requirements.

11-11.14.10 Cracks. The weld shall be free of cracks and incomplete fusion.

11-11.14.11 Burn Through. The weld shall be free of burn through.

11-11.14.12 Melt-through and repaired burn-through areas are acceptable provided the areas do not contain cracks, crevices, excessive oxidation, or globules, and provided the root convexity and concavity limits are not exceeded.

11-11.14.13 Crater pits are acceptable provided they do not contain cracks and the root concavity and convexity limits are not exceeded and the minimum weld thickness requirement is met.

11-11.14.14 Weld craters shall be free of visible cracks.

11-11.14.15 Slag. Weld surfaces shall be free of slag to the extent that there is no interference with visual or other required nondestructive tests.

11-11.14.16 Porosity. Only pores greater than 1/32 inch in diameter shall be evaluated. No single pore shall be greater than 3/32 inch in length or diameter. The sum of pore diameter in any 2-inch weld length shall not exceed 3/16 inch.

11-11.14.17 Stud Welds. Permanent welded studs shall be inspected like any other weld except friction welded studs may contain nonfusion on the legs of the flash and small shrink fissures as shown.

11-11.15 REPAIRS.

11-11.15.1 Welds repaired by metal removal (i.e. grinding, burring, arcing, chipping, etc.) or welding shall be reinspected to the original inspection requirements. Inspections of weld repairs shall be recorded on the weld record QA form.

11-11.15.2 Removal of discontinuities is only necessary to the extent required to make the weld or material acceptable to the applicable acceptance criteria.

11-11.15.3 Repair excavations shall be cleaned to sound metal and contoured to allow deposition of weld metal. The side walls shall slope, without sharp breaks or keyholing, with a bottom radius of 1/8-inch minimum. If keyholing resulting from grinding or gouging is present, additional metal shall be removed as required to permit proper electrode accessibility and manipulation.

11-11.16 ATTACHMENT WELD REMOVAL AREAS.

11-11.16.1 Attachment welds (temporary and permanent removal areas) shall have been removed by grinding, chipping, arc-air gouging, or oxy-fuel cutting. For HY-80/100 or HY-130 and high hardenable materials, removal shall have been no closer than 1/16 inch from the base material, and then followed by grinding or chipping to restore the surface. Stud welds 1/4 inch and smaller shall be removed by grinding only. Removal shall not be accomplished by bending or hammering.

11-11.16.2 After removal, the base material shall be free of all fabrication scars, arc strikes, weld spatter, and grinding marks, nicks, gouges, etc. greater than 1/32 inch in depth. The surface shall be contour ground and meet the grind undercut and contour requirements.

11-11.17 INADVERTENT INSPECTION.

Any discontinuities discovered by inadvertent inspection shall be documented and evaluated by the cognizant NAVSEA code.

APPENDIX A

TYPICAL DRY CHAMBERWELDING EQUIPMENT LOAD-OUT LIST

The following equipment is typical of that which may be required during an underwater dry welding project. The types and quantities of equipment can vary, depending on the size and complexity of the job.

1 Underwater dry chamber1 300' dry chamber umbilical1 Set of preheat pads with leads1 Underwater dry rod container1 Dry pot for underwater transfer and storage1 Industrial type seal-a-meal machine (for electrode packaging)1 Roll of seal-a-meal bags1 Set of amperage and voltage meters2 AGA masks with welding hoods2 Welding machines (300 amp minimum, 400 amp recommended)2 300' underwater welding leads4 Underwater welding stingers2 300' ground leads2 300' machine-to-knife switch leads1 Complete assortment of welding lenses1 Surface welding hood1 Set of fuel and oil filters for engine-driven welding machines1 Set of spare brushes and armature cleaner for engine-driven welding machines5 Pairs leather gloves12 Pairs rubber gloves1 Knife switch50 lbs. Duct seal- MIL-7018-M and MIL-10018-M1 welding electrodes4 Chipping hammers12 Wire brushes1 600' tool whip set for pneumatic equipment1 Pneumatic needle gun1 Set of chisels for needle gun2 Hand sledges- Grinding disks (ten 1/4", twenty 1/8")2 Wire wheels1 Complete set of oxyacetylene burning gear with gauges and spare tips1 Oxyacetylene hose repair kit2 Torch tip cleaners1 Large pneumatic grinder2 Pneumatic angle grinders1 Set underwater burning gear with spare parts kit1 Box underwater burning rods2 Hack saw with spare blades1 Torpedo level1 Framing square20 lbs. Surface welding electrodes (5 lbs. 3/32" E7018, 5 lbs. 1/8" E7018, 10 lbs. 1/8" E6010)2 Strikers2 Electric grinders8 Pairs safety glasses24 Pairs disposable ear plugs2 Pairs burning goggles1 Surface welding hood2 25' metal tape measures2 Combination squares2 Flash lights6 100' extension cords2 Drop lights with 6-pack of spare bulbs4 Magnet thermometers (0°-500°F)2 Snooperettes (or equivalent) with 300' cords for chamber lighting2 Snooperette (or equivalent) variac with spare bulbs1 Spare surface welding stinger

1 Box rags1 Electric drill with assortment of bits2 Rolls Teflon tape5 Soap stones3 Grease pencils1 Set amp tongs1 Underwater video camera2 Tapes for video1 Underwater 35mm camera5 Rolls 35mm film1 Complete magnetic particle inspection unit

APPENDIX B

TYPICAL WET CHAMBERWELDING EQUIPMENT LOAD-OUT LIST

The following equipment is typical of that which may be required during an underwater wet welding project. The types and quantities of equipment can vary, depending on the size and complexity of the job.

2 Welding machines (300 amp minimum, 400 amp recommended)1 Set of fuel and oil filters for engine-driven welding machines1 Set of spare brushes and armature cleaner for engine-driven welding machines2 300' welding leads2 300' ground leads1 300' welding machine-to-knife switch lead1 Knife switch4 Underwater welding stingers1 Complete assortment of welding lenses1 Set of amperage and voltmeters1 Set amp tongs1 600' tool whip set for pneumatic equipment2 Large pneumatic grinders2 Pneumatic angle grinders2 Wire wheels- Grinding disks (ten 1/4², twenty 1/8²)1 Pneumatic needle gun1 Set of chisels for needle gun2 In-line oilers for pneumatic equipment1 Complete set of oxyacetylene burning gear with gauges and spare tips2 Strikers1 Oxyacetylene hose repair kit2 Torch tip cleaners- Wet welding electrodes12 Pairs rubber gloves4 Chipping hammers4 Wire brushes1 Set underwater burning gear with spare parts1 Box underwater burning rods2 Hand sledges1 Torpedo level1 Hack saw with spare blades1 Framing square20 lbs. Surface welding electrodes (5 lbs. 3/32" E7018, 5 lbs. 1/8" E7018, 10 lbs. 1/8" E6010)2 Electric grinders8 Pairs safety glasses24 Pairs disposable ear plugs2 Pairs burning goggles1 Surface welding stinger with two spare heads1 Surface welding hood2 25' metal tape measures2 Combination squares2 Flash lights6 100' extension cords2 Drop lights with 6-pack of spare bulbs2 Snooperettes (or equivalent) with 300' cords for underwater lighting2 Snooperette (or equivalent) variac with spare bulbs1 Box rags1 Electric drill with assortment of bits2 Rolls Teflon tape5 Soap stones3 Grease pencils1 Underwater video camera2 Tapes for video1 Underwater 35mm camera5 Rolls 35mm film1 Underwater magnetic particle inspection unit

APPENDIX C

TYPICAL UNDERWATER WELDING PROCEDURES

C-1 GENERAL

The following two welding procedures are typical of those which have been approved by NAVSEA for dry chamber and wet welding repairs to Naval ships. These procedures may be used for welder-diver training; they may also be used by activities as guidelines in developing their own underwater welding procedures. As specified in section 6, each activity is responsible fordeveloping and qualifying their own underwater welding procedures for NAVSEA approval.

C-2 UNDERWATER DRY CHAMBER WELDING PROCEDURE FOR WELDING ORDINARY STRENGTH AND HIGHER STRENGTH CARBON STEELS USING CARBON STEEL ELECTRODES

C-2.1 Introduction. This welding procedure outlines the basic welding parameters, materials, and techniques to be used for dry chamber production welds at depths between 0 and 50 feet.

C-2.1.1 Variations in such parameters as travel speed, amperage, and voltage are dependent on production conditions. This procedure specifies the range of such variables shown to be valid based on the qualification tests performed.

C-2.2 References.

a. NAVSEA S9074-AQ-GIB-010/248, Requirements for Welding and Brazing Procedure and Performance Qualification.

b. ANSI/AWS D3.6, American Welding Society, Specification for Underwater Welding.

c. NSTM Chapter 074, Volume 1, "Welding and Allied Processes."

C-2.3 Welding Parameters.

C-2.3.1 Base Metal and Thickness Range.

a. Carbon steel, ordinary strength and higher strength, of MIL-S-22698 (Group S-1 of Reference a).

b. Thickness range, 1/8 inch to two times the qualification test specimen thickness (see Reference a).

C-2.3.2 Weld Joint Design(s). Groove and fillet.

C-2.3.3 Welding Position and Direction. All positions. When welding vertical, progression shall be up.

C-2.3.4 Welding Process. Shielded metal arc welding (SMAW).

C-2.3.5 Welding Consumables. 1/8-inch diameter MIL-7018-M electrodes of MIL-E-22200/10.

C-2.3.6 Welding Technique. This procedure is qualified for single-pass and multiple-pass welding using either (or both) the stringer bead or the weave bead technique.

C-2.3.7 Time Lapse Between Passes. No restriction on this time.

C-2.3.8 Electrical Characteristics.

a. Open circuit voltage, 60-80 volts DC.

b. Welding current type: Direct current, electrode positive (DCEP).

C-2.3.9 Preheat and Interpass Temperature. 125ºF, minimum.

C-2.3.10 Post-Weld Heat Treatment. None.

C-2.3.11 Welding Water Depth Range. 0 to and including 50 feet.

C-2.4 Electrode Handling Procedure. All electrodes are to be received in hermetically sealed containers. Once the electrodes are removed from the containers, they shall be either stored in electrode holding ovens at 225º-300ºF, or they shall be immediately sealed in plastic bags. Only enough electrodes for one day’s use should be stored in the bags, and each bag shall contain 20 electrodes.

C-2.4.1 The sealed bags shall be transferred to the dry chamber in pressurized canisters for additional protection. Once the bags are removed from the canisters, they shall not be opened until welding is to begin, and only one bag of electrodes shall be opened at one time. Once a bag is opened, the maximum exposure time of the electrodes to the chamber atmosphere is 90 minutes. Electrodes exposed for more than 90 minutes shall be discarded.

C-2.4.2 Each electrode shall be visually examined prior to use. Any electrode that appears contaminated by water, or is otherwise in poor condition, shall not be used. All electrodes must be accounted for by the diving supervisor.

C-2.5 Inspection And Quality Assurance. All procedure and performance qualification testing shall be performed as required by Reference a as invoked in Reference c.

C-2.5.1 Confirmation weld(s) shall be performed at the underwater work site. Welding, testing and inspection shall be as required by Reference c.

C-2.6 Welder Qualification. All welder-divers shall be qualified prior to production welding. Qualification testing shall be as required by Reference a as invoked in Reference c.

C-2.7 General Notes.

C-2.7.1 Cables. Welding cables shall be copper of size 2/0 or larger.

C-2.7.2 Power Supplies. Welding power supplies shall be 300 ampere or larger with a minimum 60 percent duty cycle.

C-2.7.3 Cleaning. Surfaces to be welded shall be cleaned to sound metal using grinders, wire brushes, or other appropriate means. All contaminants that produce hydrogen or oxygen, such as petroleum products or rust, must be removed. Salt deposits shall also be removed using fresh water. All joint areas shall be dry prior to welding.

C-2.7.3.1 Each weld pass shall have the slag removed prior to depositing the next weld pass. Also, any visible irregularities that may affect the quality of the weld shall be removed prior to depositing the next weld pass.

C-2.7.4 Grounds. The ground connection shall be located as close as practical to the weld joint. All ground connections shall be secure in order to inhibit any stray currents.

C-2.7.5 Protection from Shock. Rubber gloves shall always be worn under leather gloves when welding or using electrical equipment.

C-2.7.6 Electrical Switching. Electrical power for welding shall be controlled through a knife switch located on the surface near the welding power source. The switch should remain open except when welding is taking place.

C-2.7.7 Leads. All welding leads should be in good condition with no unrepaired breaks in the insulation. Only copper welding leads shall be used.

C-2.7.8 Addendums. Specific requirements for special applications will be addressed on an attached addendum sheet. Where such an addendum sheet is attached, it will become an integral part of this procedure.

C-3 WET WELDING PROCEDURE FOR WELDING ORDINARY STRENGTH CARBON STEELS USING CARBON STEEL ELECTRODES

C-3.1 Introduction. This welding procedure outlines the basic welding parameters, materials and techniques to be used for wet production welding at depths between 7 and 50 feet.

C-3.1.1 Variations in such parameters as travel speed, amperage and voltage are dependent on production conditions. This procedure specifies the range of such variables shown to be valid based on the qualification tests performed.

C-3.2 References.

a. NAVSEA S9074-AQ-GIB-010/248, Requirements for Welding and Brazing Procedure and Performance Qualification.

b. ANSI/AWS D3.6, American Welding Society, Specification for Underwater Welding.

c. NSTM Chapter 074, Volume 1, "Welding and Allied Processes."

C-3.3 Welding Parameters.

C-3.3.1 Base Metal and Thickness Range.

a. Ordinary strength carbon steel of MIL-S-22698 (Group S-1 of Reference a).

b. Thickness range, 1/8 inch to and including 1 1/8 inch.

C-3.3.2 Weld Joint Design(s). Groove and fillet.

C-3.3.3 Welding Position and Direction. All positions. When welding vertical, progression shall be down.

C-3.3.4 Welding Process. Shielded metal arc welding (SMAW).

C-3.3.5 Welding Consumables. 1/8-inch diameter BROCO Sof Touch CS-1.

C-3.3.6 Welding Technique. This procedure is qualified for single-pass and multiple-pass welding using either (or both) the stringer bead or the weave bead technique.

C-3.3.7 Time Lapse Between Passes. No restriction on this time.

C-3.3.8 Electrical Characteristics.

a. Open circuit voltage, 60-80 volts DC.

b. Welding current type: Direct current, electrode negative (DCEN).

C-3.3.9 Welding Water Depth Range. 7 to and including 50 feet.

C-3.4 Electrode Handling Procedure. Each electrode shall be visually examined prior to use. Any electrode that appears contaminated by water, or is otherwise in poor condition, shall not be used. All electrodes must be accounted for by the diving supervisor.

C-3.5 Inspection and Quality Assurance. All procedure and performance qualification testing shall be performed as required by Reference b as invoked in Reference c.

C-3.5.1 Confirmation weld(s) shall be performed at the underwater work site. Welding, testing, and inspection shall be as required by Reference c.

C-3.6 Welder Qualification. All welder-divers shall be qualified prior to production welding. Qualification testing shall be as required by Reference b as invoked in Reference c.

C-3.7 General Notes.

C-3.7.1 Cables. Welding cables shall be copper of size 2/0 or larger.

C-3.7.2 Power Supplies. Welding power supplies shall be 300 ampere or larger with a minimum 60 percent duty cycle.

C-3.7.3 Cleaning. Surfaces to be welded shall be cleaned to sound metal using grinders, wire brushes, or other appropriate means.

C-3.7.3.1 Each weld pass shall have the slag removed prior to depositing the next weld pass. Also, any visible irregularities that may affect the quality of the weld shall be removed prior to depositing the next weld pass.

C-3.7.4 Grounds. The ground connection shall be located as close as practical to the weld joint. All ground connections shall be secure in order to inhibit any stray currents.

C-3.7.5 Protection from Shock. Rubber gloves shall always be worn under leather gloves when welding.

C-3.7.6 Electrical Switching. Electrical power for welding shall be controlled through a knife switch located on the surface near the welding power source. The switch should remain open except when welding is taking place.

C-3.7.7 Leads. All welding leads should be in good condition with no unrepaired breaks in the insulation. Only copper welding leads shall be used.

C-3.7.8 Addendums. Specific requirements for special applications will be addressed on an attached addendum sheet. Where such an addendum sheet is attached, it will become an integral part of this procedure.

APPENDIX D

RECOMMENDED TRAINING PROCEDURES FOR USE INPREPARATION OF UNDERWATER WELDING QUALIFICATION TESTING

D-1 INTRODUCTION

D-1.1 Section 6 of NSTM Chapter 074 specifies the required topside welding training, qualifications, and experience required of Navy personnel preparing for underwater welding qualification. Accordingly, the information presented herein is intended for those personnel who have a reasonable understanding and knowledge of welding using shielded metal arc welding electrodes.

D-1.2 The information contained herein applies to both underwater dry chamber (UWDC) welding and wet welding. The welder-diver will not notice a great deal of difference between topside welding and UWDC welding. Other than cramped conditions in the dry chamber and encumbrances resulting from the diving gear being worn, UWDC welding is basically the same as topside welding; the welder-diver will simply need to get used to a welding arc, which is slightly different from that of topside welding. Due to the ambient pressure at depth, the UWDC welding arc is a little constricted and results in slightly different puddle action.

D-1.3 Wet welding, on the other hand, is vastly different from topside welding. In addition to the influences of water current and bubbles, the welder-diver will find that “feel” plays a greater role in the welding process — the ability to feel differences in the way the end of the electrode is burning off.

D-2 GENERAL APPROACH

D-2.1 Both UWDC and wet welding practice should be performed at a water depth of 15 feet or greater.

D-2.2 Practice should begin with bead-on-plate welds made in all four welding positions (flat, horizontal, vertical, and overhead); see 11-6.4 for welding position limitations. By depositing overlapping beads side-by-side, the welder-diver will become familiar with puddle characteristics at depth.

D-2.3 Once proficiency is obtained with the bead-on-plate welds, fillet weld specimens should be produced in each welding position. Fillet lodgments should be evaluated by visual inspection, break testing, and macro-section examination.

D-2.4 Finally, in order to obtain full underwater welding qualification as required by NSTM Chapter 074, Volume 1, practice groove butt weldments should be produced in each position. Recommended methods of testing, for purposes of practice welding, are visual inspection, radiographic inspection, bend testing, and macro-section examination.

D-2.5 Welding techniques for UWDC welding are basically the same as those for topside welding. Welding techniques for wet welding are addressed in section 8. Underwater welding troubleshooting criteria are covered in section 10.

D-3 BASE METALS

D-3.1 D-3.1 Base metal should be ordinary strength steel of MIL-S-22698, or any scrap carbon steel readily available. Alloy steels, or carbon steels with high carbon equivalent (see section 4), should not be used due to the possibility of base metal cracking.

D-3.2 D-3.2 Recommended base metal thickness is 3/8 inch or greater for both UWDC welding and wet welding. After proficiency in wet welding is obtained using the thicker material, the trainee should begin practicing using 1/8-inch base metal.

D-4 WELDING PROCEDURES

D-4.1 Bead-On-Plate (BOP) Welding. BOP welds should be performed until the trainee is able to deposit side-by-side beads that meet the visual inspection requirements of section 6 of NSTM Chapter 074, Volume 1. This requires a bead overlap resulting in a smooth transition between beads without undercut. Valleys between beads should not exceed 1/32 inch in depth. For wet welding, the trainee may wish to deposit the first bead top-side; this should provide a guide which will allow the remaining beads to be deposited fairly straight.

D-4.1.1 It is suggested that the above BOP welding be performed using both DCEP and DCEN polarities during wet welding; this will better prepare the trainee for variations in wet welding behavior that can occur during underwater welding operations (see section 10).

D-4.1.2 Once wet welding proficiency is obtained at a water depth of 15 feet or greater, the trainee should perform similar welding at a water depth of 5 to 7 feet. Depending on the electrode being used, the trainee may find that the weld metal is influenced a little more by gravity at the shallower depth — especially in the overhead position.

D-4.2 Fillet Welding. As with BOP welding, fillet welding should be carried out in all four positions. The trainee will notice two primary differences when changing from BOP welding to fillet welding.

a. The puddle becomes more confined and easier to handle

b. More rod pressure is required

D-4.2.1 The increased rod pressure is required to enhance penetration during the initial (root) pass. Once the root pass has been deposited, the rod pressure will be reduced. The initial practice welding should be directed toward satisfactory deposition of the root pass, with a weld profile somewhere between slightly concave to slightly convex (see ANSI/AWS D3.6). Once an acceptable fillet weld profile is obtained, an evaluation should be made for weld quality and penetration using the fillet break test as described in D-5 below.

D-4.2.2 After developing the skill for satisfactory deposition of the root pass, additional passes should be deposited over the root pass to provide a fillet weld size (see section 3) of 3/8 inch or greater. The fillet weld contour should meet the visual acceptance standards of section 6 of NSTM Chapter 074, Volume 1. Bead overlap should be as outlined above for the BOP welding. Once an acceptable multiple-pass fillet weld profile is obtained, an evaluation should be made for weld quality and penetration using the fillet break test described in D-5 below.

D-4.3 Groove Butt Welding. Groove butt welding practice and testing will quickly show the competence level of the trainee, since weldment evaluation is more detailed and more likely to reveal weld discontinuities which would have been missed during BOP and fillet welding testing. To put it another way, groove butt weldment evaluation is less forgiving of welding mistakes.

D-4.3.1 For wet welding practice, the weld should be made against a backing bar as shown in Figure D-1.

D-4.3.2 For UWDC welding, the practice welding can be made against a backing bar as shown above, or the plates can be butted together without the backing bar — in which case the weld joint would be completed, after which the backside would be ground or gouged to sound metal and rewelded to obtain a sound weld root.

D-4.3.3 When wet welding using the above joint design, it is best to leave a root opening (1/4 to 3/8 inch when using a 1/8-inch electrode) large enough to deposit a two-pass root. This allows the trainee to concentrate on tying in each side of the root separately. When depositing the root passes, the technique is basically the same as that used for making the root pass of a fillet weld.

D-4.3.4 Since root pass deposition requires the greatest skill, it is wise to limit initial evaluations to the root passes. Thisevaluation should consist of visual inspection and macro-section examination. Once satisfactory root pass deposition techniques have been confirmed, fully welded joints can be produced and evaluated.

D-4.3.5 Visual inspection of the completed weldments should meet the standards described above for the BOP and fillet weldments. Radiographic inspection is recommended to verify that invoked acceptance criteria are met while providing a method of weeding out those weldments which may contain gross weld defects to the extent that destructive testing is not warranted.

D-4.3.6 Once weld quality has been confirmed by nondestructive testing, destructive testing by bend testing and macro-section examination should be performed as specified in D-5.

D-4.4 Welding Variables. The primary welding variables of interest for purposes of this appendix are:

a. Amperage

b. Voltage

c. Travel speed

D-4.4.1 Recommended ranges for amperage and voltage, and occasionally travel speed, will be provided by the electrode manufacturer. Section 5 addresses approved electrode manufacturers as well as amperage and voltage meters. During initial practice welding, amperage is the variable that is of the greatest importance. Once the amperage is adjusted to obtain

acceptable bead appearance, the arc voltage should be close to the optimum required (acceptable weld beads require proper arclength; arc length controls arc voltage). It should be remembered that both amperage and voltage will vary as the welding progresses, since the arc length does not stay constant. The longer arc gives increased arc voltage (more resistance) and thus reduces the amperage, and vice versa.

D-4.4.2 D-4.4.2 As the welder-diver refines his technique, closer attention can be paid to arc voltage and travel speed. Observation of arc voltage will show arc length variations which can show problem areas that may not be obvious to the welder-diver while welding is progressing. The range of travel speeds that produce acceptable results should be recorded to allow additional input in developing optimum welding techniques. Travel speed is the speed at which a weld bead is deposited in inches per minute; it is calculated as follows:

Travel speed = (Length of bead in inches / time in seconds) x 60

D-5 WELDMENT EVALUATION BY DESTRUCTIVE TESTING

D-5.1 For purposes of this document, two methods of destructive testing should be considered; both methods are described below. Additional information and acceptance criteria for these destructive testing methods are specified in section 6 of NSTM Chapter 074, Volume 1 and the referenced specifications invoked therein.

D-5.1.1 Fillet Break Testing. This testing method is used to evaluate internal weld quality and penetration. The weld is broken open by bending or hammering in a direction to cause the weld to fracture in tension as shown in Figure D-2. This test can easily be performed in the field by using, for example, a vise and a sledge hammer.

D-5.1.1.1 In evaluating penetration, adequate penetration shows weld metal extending at least to the edge of the web member of the above “T” specimen. Slag entrapment in the root can interfere with penetration. The slag can be seen in the fillet weld break, or where the slag has fallen out, there will be a shiny area with ripples similar to the surface of a weld. Note that fillet breaks will be easier to break if the tack welds are ground off.

WARNINGNitric acid can cause serious burns and shall be handled cautiously. When mixing acid and alcohol, the acid shall

always be poured into the alcohol.

D-5.1.2 Macro-Section Examination. This examination can be used for both the BOP welding and the fillet welding. A cross section of the weldment is removed by sawing, exposing the weld and adjacent base metal. The cross-section is then ground or sanded to produce a flat, smooth finish of 60 grit or finer. An etching solution of 90 percent denatured alcohol/10 percent nitric acid can then be wiped onto the surface (using a cotton swab, for example) to bring out weld and heat-affected zone details. The etching solution should be washed off, using denatured alcohol, as soon as the microstructural details become visible; this should occur in less than 1 minute.

D-5.1.2.1 The 60-grit finish will show minimal details of weld quality. A finer finish (i.e. 400 grit) gives a more detailedpicture of weld quality and the heat effects of welding. The finer finish also requires less time for etching.

D-5.1.2.2 Macro-section examination provides an accurate picture of weld penetration and allows evaluation for small weld defects that might not be otherwise detected.

D-6 ADDITIONAL CONSIDERATIONS

D-6.1 In planning for the practice welding detailed above, the welder-diver trainee should be prepared to spend a significant number of man-hours “burning rods”; no one reaches any degree of underwater welding competence without a lot of arc time, and this is especially true of wet welding. Once proficiency is reached using base metal approximately 3/8 inch thick, the trainee will find that welding on thin materials (e.g., 1/8 inch and less) will require some significant changes in welding techniques. All in all, and especially for wet welding, a good deal of time will be required to develop the competency required for successful underwater welding qualification.

D-6.2 However, it should be understood that passing qualification testing, under ideal welding conditions, does not necessarily guarantee that the welder-diver will be able to perform underwater welding of equivalent quality during an actual production welding underwater repair. As described in section 8, water current, fit-up problems, and many other factors can influence weld quality. It is only after numerous production underwater welding jobs, where on-site problems are encountered and overcome, that the welder-diver truly becomes proficient in the work.