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WLD 257

Preparation for Pipe Certification II

WLD 257 6/11/12

Matt Scott

2

Index Pages

Course Information 3

Science on Steel

4-10

Pipe Prep and Welding Information

Sheets

11-37

Craftsmanship Expectations 38

Welding Projects

39-42

Final Exam Information

43-49

Assessment Breakdown for the Course

50

Video Training Pipe Welding Made Easy

SMAW E6010/E7018 6G

SMAW E6010/E7018 5G

Located in the Welding Resource Room

This project was supported, in part,

by the

National Science Foundation Opinions expressed are those of the authors

And not necessarily those of the Foundation

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Course Assignments

Reading

WLD 257 Information Sheets

Welding Projects

6G Butt - Single Vee Grove Weld - Open Root - Pipe Weld

5G Butt - Single Vee Grove Weld - Open Root - Pipe Weld

Video Training

Pipe Welding Made Easy E6010/E7018 6G

Pipe Welding Made Easy E6010/E7018 5G

Final Exam

Part One (Closed Book Exam)

Part Two (Practical Exam)

Outcome Assessment Policy:

The student will be assessed on his/her ability to demonstrate the achievement of course

outcomes. The methods of assessment may include one or more of the following: oral or

written examinations, quizzes, written assignments, visual inspection techniques, welding

tests, safe work habits, task performance and work relations.

Grading criteria:

The student's assessment will be based on the following criteria:

15% of grade is based on safe work habits and shop practices.

20% of grade is based on completion of written and reading assignments.

15% of grade is based on demonstrating professional work ethics.

40% of grade is based on completion of welding exercises.

10% based on final exam/project

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Science

on

Steel

The Welding Fabrication Industry needs qualified welder fabricators who can deal with a

variety of situations on the job. This portion of the training packet explores science as it

relates to industry requirements.

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E6010/E7018 Pipe Certification

Contents of this Packet

- Introduction

- Importance of Code Qualification

- Mechanical Properties Testing for Pipe Welding Qualification

- Code Requirements

- Significance of Bend Testing

- Concave Root Surface (Suck Back)

Introduction

This packet covers the welder qualification using the combination of E6010 cellulosic

electrode for the root pass and E7018 low-hydrogen electrodes for subsequent fill passes

deposited in open root pipe welding on mild steel. Although the E6010 and E7018

electrodes operate differently (as discussed in previous science packets), the testing

required for welder qualification for most pipe welding codes are similar. E6010 is the

deepest-penetrating, all-position electrode. To achieve such deep penetration, the highest

amount of cellulose is used in the flux cover. The cellulose also provides large amounts

gaseous shielding with minimal slag. This allows the welder to have a clear view of the

keyhole in open root welding. On the other hand, the fill passes are deposited with

E7018, which is a lime-based, iron-powder, low-hydrogen electrode. Unlike E6010, the

E7018 electrode provides high deposition rate as well as a thick slag to generate the

primary source of shielding. Because E6010 is a high-hydrogen electrode, the welder

must be certain that the code (he/she is using) allows the use of cellulosic electrodes. If

not, all of the passes including the root pass must be deposited with the low-hydrogen

E7018 electrode (even though E6010 is the best electrode for open root welding). In

some cases, the root pass is deposited by gas tungsten arc welding.

Importance of Code Qualification

In all industries, there are applicable codes and standards to assure the quality,

reproducibility, and adequacy of welded joints. Depending upon the application, a

welded joint may need certain mechanical properties; for example, welds on bridges must

pass tests for strength, tensile ductility, bend ductility, and Charpy impact toughness.

These codes are based on many years of experience. Changes to codes are ongoing to

reflect the dynamic changes that taking place in the industry. There are many welding

codes to ensure quality welding. For example, the following is a list of only a few typical

industries and governing codes for welding quality.

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Pressure Vessel ASME Boiler and Pressure Vessel Code

(Vol. IX – Welding Qualifications

Pipe and Pipelines API Standard 1104; Standard for Welding

Pipelines and Related Facilities

Pressure Piping ASME Code for Pressure Piping B31

All Steel Structures AWS D1.1 Structural Welding Code –

Steel

Buildings AISC Specification for Structural Steel

Buildings

Bridges AASHTO/AWS D1.5; Bridge Welding

Code

Ships ABS Rules for Building and Classing Steel

Vessels

Sheet Metal AWS D9.1; Sheet Metal Welding Code

Automotive Frames ANSI/AWS D8.8; Specification for

Automotive Frame Weld Quality

Aircraft MIL-STD-1595A; Qualification of

Aircraft, Missile, and Aerospace Fusion

Welders

Mechanical Properties Testing for Pipe Welding Qualification

In all codes for welded structures and pipe, various degrees of mechanical testing are

performed to assure the quality and integrity of the structure. This includes both

procedure qualification and welder qualification. For example, the procedure

qualification for pipe as well as steel structures in accordance with the AWS D1.1

Structural Steel Welding Code requires that certain welds undergo all-weld-metal tensile

testing, transverse-to-weld tensile testing, side bend testing, Charpy v-notch (CVN)

impact testing as well as non-destructive testing. Mechanical testing is very important

because it ensures that the welding procedure, welder qualification, consumables, and the

resulting metallurgy of the weld and heat-affected zone were all acceptable. Welder

qualification generally requires less mechanical testing than the procedure qualification;

for example, welder qualification typically includes visual, non-destructive testing, and

face bend and root bend testing.

Code Requirements

When a pipeline or pressure piping is going to be built, the owner and contractor agree on

the appropriate welding code, which will be needed to govern the acceptability or

rejection of structural welds being fabricated. API-1104, ASME Boiler and Pressure

Vessel Code and AWS D1.1 Structural Welding Code can be used for pipe and tubing

applications. Codes are devised to provide welded joints with acceptable strength,

ductility, and CVN impact toughness for the intended application. These codes also

provide for procedure qualification requirements and welder qualification requirements.

The qualification and certification tests for welders are specially designed to determine

the welder’s ability to produce sound welds routinely. To achieve these quality standards,

the welder qualification and certification provide the means to ensure acceptable welds.

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Significance of Bend Testing

Of all the tests prescribed by different welding codes, the bend test provides the best and

most reliable measure of ductility of the entire weld joint, including the weld metal, heat-

affected zone, and unaffected base metal. Welder qualification tests in AWS D1.1 always

specify bend testing of welded joints. This is because the bend test is extremely sensitive

to all types of metallurgical problems associated with welding. For example, weld joints

which have inadequate ductility and fail the requirements of the bend test may be due to:

(a) hydrogen assisted cracking, (b) microfissuring due internal solidification cracking, (c)

excessive slag inclusions, (d) excessive porosity, (e) wrong filler metal, causing

embrittlement, (e) wrong welding parameters, causing embrittlement, and (f) other

metallurgical factors affecting the ductility of the weld joint.

There are three types of bend tests, (1) side bend, (2) face bend, and (3) root bend. Side

bend tests are generally required for welds that are greater than 3/8-inch thick for AWS

D1.1 and over ½-inch thick for API-1104. For example, a 2-inch thick butt joint

deposited by single-pass electroslag welding could not be tested by face or root bend

testing because the thickness is too great for practical testing. However, a 2-inch thick

butt joint can be machined to several 3/8-inch thicknesses and tested by side bending.

So, face and root bending are used to test the ductility of butt joints that are thinner than

3/8-inch. Whether face bends, root bends, or both face and root bends specimens are

required depends upon the code used. In AWS D1.1 Structural Welding Code, both face

and root bends are required in most cases. The root bend test determines the adequacy of

the root preparation and soundness of the root portion of the weld joint. This is

particularly important in open root welding applications. Similarly, the face bend test

determines the adequacy of the weld metal deposited on the face of the joint. These

specimens must be able to withstand bending strains that are produced when a plunger

forces a 3/8-inch thick welded specimen into a guided bend fixture. The plunger, having

a specified bend radius, forces the welded bend specimen into a die in order to endure a

specified amount of bending (or plastic deformation), that is required by the code for

structural applications. From Table 1, the plunger radius and plunger thickness increase

with increasing yield strength of the base metal being tested. Bending becomes more

difficult with increasing yield strength, because ductility decreases as the strength of the

steel increases. Thus, AWS D1.1 permits the bend radius required for welder

qualification to increase with increasing yield strength, as shown in Table 1.

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Table 1 Specified Bending Parameters for Guided Bend Test for Steel Welds

in accordance with AWS D1.1 Structural Welding Code - Steel

Yield Strength

Of Base Metal

Plunger

Thickness

Plunger

Radius

Interior Die

Opening

Die Radius

50,000psi and

less

Over 50,000psi

to 90,000psi

90,000psi and

greater

1 ½”

2”

2 ½”

¾”

1”

1 ¼”

2 3/8”

2 7/8”

3 3/8”

1 3/16”

1 7/16”

1 11/16”

Furthermore, the bend test for steel welds is very sensitive to the presence of diffusible

hydrogen in the weld. Even if non-destructive testing shows a welded steel to be crack-

free, the bend test can activate the hydrogen cracking mechanism in steel welds which are

susceptible to hydrogen cracking. Thus, there are many metallurgical causes for lack of

adequate ductility in a welded structure, and the bend test is best suited to separate the

“good” welds from the “bad” welds.

Concave Root Surface (Suck Back)

The root pass of an open root weld often exhibits “suck back” or a concave root surface in

pipe joints as well as open root plate joints. This is due to a complex set of forces, which

simultaneously act upon the molten metal in the bottom of the open root. As the open

root pass begins to solidify, the weld shrinks and the remaining liquid is stretched across

the root face to form a concave root surface or suck-back. The liquid can actually stretch

to some degree without burn-through because surface tension acts to hold the molten

metal together.

The three most important forces acting on the root pass are (1) surface tension of the

molten metal, (2) gravity, and (3) arc force. None of these forces are easily controlled by

the welder. Surface tension is a beneficial property of the molten weld metal, which

tends to hold molten metal together, much like a balloon holds liquid water. Surface

tension forces increase with decreasing temperature of the molten weld metal. Gravity

always tries to oppose the beneficial effects of surface tension of molten metal in the open

root. The effects of gravity are dependent upon the size and weight of the weld pool as

well as the welding position used; for example, flat, compared to overhead, compared to

vertical-up. The larger the weld pool size of the root pass, the more difficult it will be for

surface tension to hold the molten metal in place. Arc force is another complex force,

which is provided by the arc in the direction of arc impingement. Arc force increases

with increasing amperage. Too high an arc force will burn through the root. With

decreasing amperage and decreasing size of root pass, the greater will be the surface

tension forces holding the molten pool in place.

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Surface tension is the most important beneficial force, because without surface tension,

open root welding would not be possible. Without surface tension, the molten metal in

the open root would act like water and flow through the root opening. Surface tension is

always trying to keep the molten pool from dripping out of the root area. Imagine a

balloon full of water, the elastic polymer provides the restraining forces to keep the water

in place. If outside forces are too great, the balloon will distort, burst and water will

escape. Similarly, in a full-penetration open-root pass, the heat input must be adjusted so

that surface tension will hold the molten in the open root opening. The smaller the root

pass, the easier it is for surface tension forces to hold the molten metal in place. When

the root pass is deposited by E6010 electrode, just the right amount of heat input is

needed to produce a keyhole in the joint for full penetration. With too little heat, full

penetration will not be achieved; while, with too high heat input, the arc will blow

through the joint. At the optimum level of heat, the molten metal is suspended by surface

tension forces in the gap of the open root. Surface tension forces overcome gravity and

the root pass is achieved.

Quantitatively, the resolved force (F) acting on the weld pool is function of two opposing

factors; surface tension force and gravitational force, as shown below:

F = + P γ - ρ g V

P is the periphery length along the root face, γ is the surface (tension) energy, ρ is the

molten metal density, g is the acceleration of gravity, and V is the volume of molten

metal in the root gap. From this equation, increasing the beneficial surface tension (P γ)

force prevents drop-through or burn-through by holding the molten metal in place. Also,

the fast freezing flux is very helpful in supporting the suspended molten metal between

the two plates. However, the weight of the molten (- ρ g V) is affected by gravity and

tries to prevent successful open root welding. Increasing the heat input promotes larger

molten pool size and higher molten pool temperatures. This causes a reduction in the

surface tension forces holding the weld in place.

How does “suck back” develop in the root and what controls the amount of suck back?

Surface tension is necessary to hold and suspend the molten metal in the open root

without dropping through like water. Surface tension of molten metal in the open root

acts as if the molten metal is in an “impervious bag” which prevents liquid from falling

through the open root. Fortunately, the surface tension of molten iron is very high; for

example, the surface (tension) energy of iron at its melting point is about twice that for

aluminum at its melting point. So during solidification, the shrinkage forces between the

two root faces pull on the molten pool substantially to produce a concave root surface or

suck back. Suck back can be overcome if the welder can provide additional weld metal

into the root. This is dangerous because of the increased chance of drop-through.

Fortunately, in welding, the use of fast freezing fluxes and good welder skill reduce the

occurrence of excessive concave root surfaces.

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Science on Steel Questions – WLD 257

Name: ____________________________ Date: ___________________

1. Why is mechanical testing in pipe welding important?

2. List 3 common welding codes that can govern a piping system.

3. Why are bend tests significant to the welder qualification and procedure qualification

process?

4. What are the three types of bend tests?

5. What are three factors that affect suck back in pipe welding?

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Watts Pipe Cutter Information Sheet

• The Watts pipe beveler uses oxygen and acetylene to flame cut pipe bevels. All

safety procedures that apply to the track burners and hand torches apply with this pipe

beveler.

• Place pipe in jaws and snug jaws down with T-bar wrench.

• Swivel cutting head over pipe ensuring there is approximately ¾” clearance between

the cutting tip and pipe.

• Slowly hand rotate the pipe, referencing the cutting tip to pipe wall distance. For a

quality cut this variation should not exceed 1/16”. Make adjustments when necessary

• Tighten jaws after alignment is completed.

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Watts Pipe Cutter Information Sheet Continued

• Turn on manifold and adjust cutting pressures. A good starting point is 5 psi for

acetylene and 40 psi for oxygen.

• Turn the Ignite toggle switch ON and open the acetylene needle valve on the back

side of the unit. Light the torch and adjust the acetylene flame so the heavy soot

disappears.

Cut Roll Switch

Ignite Switch Fast Roll Switch Acetylene Valve Oxygen Valve

Front Side Back Side

• Add oxygen, and adjust to a neutral flame.

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• Turn the Cut and Roll toggle switch ON and adjust to a neutral flame. When adding

the cutting oxygen, the fuel gas to oxygen ratio changes thus requiring the need to

readjust to a neutral flame.

• Once flame is adjusted, the manual needle valves do not need to be turn off each time.

Use the Ignite toggle switch to turn the torch ON and OFF.

Rotation Speed Control

Ignite Toggle Switch Fast Roll Switch Cut Roll Switch

• Light torch and align head over the pipe. Use the Fast Roll toggle switch and preheat

the pipe by having it rotate 360 degrees. Once pipe is preheated let the torch set idle

over one area to heat the kindling temperature (cherry red).

Helpful Hint: Clamp vice grips at the cutting start point. This is a good visual

reference for when the pipe cut will be completed, as well as a tool to catch the

pipe coupon.

• Once pipe is cherry red, turn the Cut and Roll toggle switch on and the cut will begin.

Helpful Hint: Once flame pierces through the pipe, adjust the torch back slightly

to remove the starting flaw.

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Torch Extension Arm

• Once pipe cut is completed, adjust torch extension arm back to make additional cuts

or remove pipe coupon and replace with next coupon and complete the cutting

process.

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Watt’s Pipe Grinding Station Information Sheet

• Ensure pipe is cool enough to handle before handling it.

• Mount pipe in the rotating fixture ensuring that it is mounted concentrically.

• Tighten the thumbscrew ensuring that the pie is secure.

Thumb Screws

• Hand start the pipe fixture rotation and then begin grinding the groove face.

• Ensure grinder has enough clearance, so it does not hit or catch on the rotating fixture.

Watt’s Pipe Grinding Station Information Sheet Continued

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• Do not let the fixture rotate too fast. Slow it down frequently, so that the pipe is not

thrown from the fixture.

• Ensure the grinder is placed in such a way that the sparks are shooting downward.

• Ensure screens are in place so no by standers are showered with sparks.

• Grind the groove face clean, and then grind the land. For the up hill root pass

technique, use a “nickel land” (the land is ground to a thickness of a nickel which is

approximately 3/32”).

• Once grinding is completed, remove pipe coupon, replace with next coupon and

complete the grinding process.

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Fitting Up the Pipe

1. “Dry” fits pipe together and rotate top pipe to determine best fit-up to eliminate

high-low condition and excessive root opening. Once the best fit-up is

determined, draw a soap stone line to indicate placement of pipe coupons to assist

alignment after the spacer is put into place.

High Low

A high-low condition refers to the pipe material being offset at the fit up

area. This is because each pipe coupon is not a perfect circle. The

ASME Code only allows 1/16” for high low.

2. Place a spacer wire between the pipes for the proper root opening. Rotate the top

pipe to minimize a high low fit-up.

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3. Make the first tack weld ½” long between the open ends of the spacer wire. The

first tack should only be ½” long to help control distortion. The remaining three

tacks should be ¾” long.

4. Remove the spacer wire and reposition it as shown, and weld the second tack

opposite the first tack (this is referred to as diametrically opposed to the first tack).

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5. Tack weld the two remaining sides starting with the wider of the two sides. At

this point the pipe should have one tack weld at 12, 3, 6 and 9 o’clock positions.

6. Use a hand grinder with a 1/8” thick notching wheel to feather (ramp) the tacks.

The keyhole side of the tack will not need as much grinding. Too much grinding

on this end of the tack will potentially cause burn through when welding the root

pass.

Minimal grinding at the key hole end

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Pipe Welding Power Tools

At a minimum a pipe welder should have:

• Two 9 inch grinder for pipe that is 6 inches and larger (one with a notching wheel

and one with a wire wheel).

• Two 4½ inch grinder for 4 inch pipe and smaller (one with a notching wheel and one

with a wire wheel).

• File with “teeth ground in it” used for slag removal (Do Not Use a Chipping

hammer on Pipe).

• Flash light for inspection purposes.

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6G Welding Techniques

1. Secure the pipe in the fixture in the 6G position to be welded.

6G Position

Pipe axis is inclined 45 degrees from the horizontal plane

1. Strike the arc and extend the arc length (“long arc”) over the tack weld and allow

electrode to "warm up.” "Pop" the electrode into open root and pause slightly, and

begin welding. Note that the Arc is “burning” through the root opening getting

complete penetration. This is seen by the keyhole that the arc creates.

Strike the arc on the tack weld The “fire” is inside of the pipe.

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2. Use the whip and pause technique for the root pass, pushing the electrode no more

than half way into the root area. Ensure that the "fire" stays on the back side of

the pipe. This will create the distinctive sound when obtaining 100%

penetration.

The small stepping motion will allow the puddle to freeze and the root pass will

be easily worked forward. Use a forward “stepping” motion of 1/2 to 1 electrodes

diameter, and then returning the electrode to the keyhole. It is important to touch

down" in the puddle to help fill undercut on the backside.

Whip and Pause Technique

Keep the arc tight and step no more than 1 electrode diameter in distance.

Root Pass Arc Length

Keep a tight arc when touching down into the puddle. Try not to push electrode

more than ½ way into the root face area.

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Use the two handed technique to strike

the arc. This will help eliminate arc

strikes on the pipe wall that will render

the pipe useless.

This technique is sometimes referred to

as “shooting pool.”

While welding keep the root pass

centered in the root opening and moving

forward. There is nothing but the

puddle to catch itself on the backside of

an open root weld so a slow travel speed

will lead to excessive root reinforcement.

Note that the lumpy areas are not

detrimental since the root pass will be

ground before applying the hot pass

Five variables to control when applying the root pass:

• Root face

• Root opening

• Amperage

• Arc length

• Travel speed

The soundness of the root pass will be greatly affected by these five variables. The

welder will need to learn to control these variables to produce a quality root bead.

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Root Bead Suggestions:

• Center root pass (stringer) in the root opening when welding, this will help prevent

internal undercut or inadequate penetration (IP).

• Keep the bead moving

• Avoid letting the key hole get too large

• Vary technique for joint fit up.

Adjust Technique for Root Fit Up to ensure 100% penetration

Narrow gap techniques:

• Push electrode into opening to “burn through”

• Increase amperage

• Grind root area to reduce root land

Wide gap technique:

• Weld wide section last. Hopefully welding the other three quadrants will shrink wide

area.

• Reduce current

• Use U-weave whip and pause technique

• Allow the pipe to cool.

Internal Undercut:

• Electrode too deep into groove

• Amperage too high

• Root opening too large

• Root land too thin

Stopping techniques

Use a quick step out of the root bead to decrease keyhole size when terminating

the weld. Leaving a large keyhole can cause excessive root reinforcement on the

inside.

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Root Pass inspection

A quality root pass

• Remove the slag from the internal root pass side. Inspect the root for complete

penetration, undercut and excessive penetration. See Craftsmanship Expectations for

inspection criteria.

Applying the Hot Pass

Grind out face of root bead to prepare for the hot pass

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• Increase amperage 10 to 20 amps above root bead setting.

• The whip and pause technique should be used with whipping distance 1 to 2

electrode diameters with a medium arc length. Use a circling technique “Paint The

Walls” to remove wagon tracks.

The purpose of the hot pass:

• Burn out slag (wagon tracks)

• Re-contour stringer

• Anneal (stress relieve)

• Drive out hydrogen in heat affected zone (HAZ)

Low Hydrogen Fill and Cover Pass Technique

A tight arc essential when welding with E7018. The puddle relies on the vaporization of

the flux and the molten slag for shielding. Keep the electrode in the puddle at all times,

No Whipping Out of the Puddle, to produce a sound weld.

Failure to follow these techniques may result in porosity, undercut, slag inclusions, or

lower impact strength.

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First layer of the 7018 fill pass

• Use the slant loop technique to cover the whole hot pass. Pause at the side walls and

not the middle of the puddle.

• Remove all slag prior to applying next layer

Second layer of the 7018 fill pass:

• Use the slant loop multiple pass stringer bead technique for the second layer of fill

beads.

• Ensure to leave enough area for the second pass on this layer. If the first bead is too

large there will not be enough room for the second bead to go in with out trapping

slag.

• Remove all slag prior to applying next layer.

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Cover Passes (Finish Beads) for the 6G

• Use the Slant Loop Stringer Bead Technique

Slant Loop Technique

• For the 6G weld, the maximum bead width should not be more than ½” wide.

Excessively wide beads will lead to over lap.

• Remove all slag with a wire wheel. Note that a hand file can be used to smooth out

undercut at the weld and the pipe wall interface (toe). Excessive filing will not be

permitted because it reduces the pipe wall thickness.

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5G Welding Techniques

1. Tack weld pipe coupons together and secure the pipe in the fixture in the 5G

position to be welded.

5G Position

Pipe axis is parallel to the horizontal plane

and the pipe is not rotated

2. When applying the root pass, strike the arc and extend the arc length (“long arc”)

over the tack weld and allow electrode to "warm up.” "Pop" the electrode into

open root and pause slightly, and begin welding. Note that the Arc is “burning”

through the root opening getting complete penetration. This is seen by the keyhole

that the arc creates while welding.

Strike the arc on the tack weld

The “fire” is inside of the pipe which

creates a distinctive beehive sound

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3. Use the whip and pause technique for the root pass pushing the electrode no more

than half way into the root area. Ensure that the "fire" stays on the back side of

the pipe. This will create the distinctive sound when obtaining 100% penetration.

The small stepping motion will allow the puddle to freeze and the root pass will

be easily worked forward. A forward “stepping” motion of 1/2 to 1 electrodes

diameter, and then returning the electrode to the keyhole should be used. It is

important to "touch down" in the puddle to help fill undercut on the backside.

Whip and Pause technique

Keep the arc tight and step no more than 1 electrode diameter in distance.

Root Pass Arc Length

Keep a tight arc when touching down into the puddle. Try not to push electrode

more than ½ way into the root face area.

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Use the two handed technique to strike

the arc. This will help eliminate arc

strikes on the pipe wall that will render

the pipe useless.

This technique is sometimes referred to

as “shooting pool.”

Keep the root pass centered in the root

opening and moving forward. There is

nothing but the puddle to catch itself on

the backside of an open root weld.

Traveling too slow will lead to excessive

root reinforcement.

Note that the lumpy areas are not

detrimental since the root pass will be

ground before applying the hot pass.

Five variables to control when running the root pass:

• Root land

• Root opening

• Amperage

• Arc length

• Travel speed

The soundness of the root pass will be greatly affected by these five variables. The

welder will need to learn to control these variables to produce a quality root bead.

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Root Bead Suggestions:

• Center root pass (stringer) when welding, this will help prevent internal undercut or

inadequate penetration (IP).

• Keep the bead moving

• Avoid letting the key hole get too large

• Vary technique for joint fit up.

Adjust Technique for Root Fit Up to ensure 100% penetration

Narrow gap techniques:

• Push electrode into opening to “burn through”

• Increase amperage

• Grind root area to reduce root land

Wide gap technique:

• Weld wide section last. Hopefully welding the other three quadrants will shrink wide

area.

• Reduce current

• Use U-weave whip and pause technique

• Allow pipe to cool.

Internal Undercut:

• Electrode too deep into groove

• Amperage too high

• Root opening too large

• Root land too thin

Stopping techniques

Use a quick step out of the root bead to decrease keyhole size when terminating

the weld. Leaving a large keyhole can cause excessive root reinforcement on the

inside.

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Root Pass inspection

A quality root pass

• Remove the slag from the internal root pass side. Inspect the root for complete

penetration, undercut and excessive penetration. See Craftsmanship Expectations for

inspection criteria.

Hot Pass (Whip and Pause)

Grind out face of root bead to prepare for the hot pass

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Applying the Hot Pass

• Increase amperage 10 to 20 amps above root bead setting.

• The whip and pause technique should be used with whipping distance 1 to 2

electrode diameters with a medium arc length. Use a circling whip and pause

technique to “Paint The Walls” to remove wagon tracks.

The purpose of the hot pass is to:

• Burn out slag (wagon tracks)

• Re-contour stringer

• Anneal (stress relieve)

• Drive out hydrogen in heat affected zone (HAZ)

Low Hydrogen Fill and Cover Pass Technique

A tight arc essential when welding with E7018. The puddle relies on the vaporization of

the flux and the molten slag for shielding. Keep the electrode in the puddle at all times,

No Whipping Out of the Puddle, to a produce a sound weld.

Failure to follow these techniques may result in porosity, undercut, slag inclusions, or

lower impact strength.

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First layer of the E7018 fill pass

• Use the side-to-side weave technique to cover the whole hot pass. Emphasize the side

walls when welding not the middle of the puddle.

• Remove all slag prior to applying next layer

Second layer of the E7018 fill pass:

• Use the side-to-side weave bead technique for the second layer fill bead.

• Ensure to leave enough area for the cover pass.

• Remove all slag prior to applying next layer.

Example of the side-to-side technique for

the fill passes.

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Cover Passes for the 5G

Use the same side-to-side technique for

the cover pass.

• Use the Side-to-Side Weave Bead Technique

• For the 5G weld, the maximum bead width should not be more than 1/8 larger than

the groove opening. Excessively wide beads will lead to a sloppy appearance and a

waste of time and filler material.

• Remove all slag with a wire wheel. Note that a hand file can be used to smooth out

undercut at the weld and pipe wall interface (toe). Excessive filing will not be

permitted.

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Vocabulary for Common Pipe Welding Defects

Arc Strikes

Starting the arc outside the weld area. This leaves “hot spots” which can causes

undercut and cracking

Cracks

An area where the stresses in the weld metal exceed the strength, thus causing a

fracture.

Undercut (Internal and External)

A groove melted into the base metal adjacent to the toe or the root of a weld and

left unfilled by the weld metal.

Overlap/cold lap

The protrusion of weld metal beyond the toe, face, or root of the weld. The weld

“rolls.”

Slag Inclusion

A nonmetallic solid entrapped in the weld metal or between the weld metal and

the pipe material.

Porosity

Gas pockets or voids occurring in the weld metal (swiss cheese).

Incomplete Fusion (IF)

A lack of bond between weld beads or between weld metal and the base metal.

Inadequate Penetration (IP)

Incomplete filling of the weld root with weld metal. Not breaking the walls

down.

Internal Concavity (Suck Back)

A root bead which is properly fused but is the center of the bead is slightly

below the inside of the pipe wall.

Underfill

Not enough weld metal to completely fill an area.(Weld groove)

Wagon Tracks

Slag inclusion between the root pass and the hot pass that run parallel to each

other.

Hollow Bead

Elongated linear porosity occurring in the root pass due to excessively high travel

speeds.

Burn Through

The portion of the root bead where excessive penetration has caused the weld

puddle to be blown into the pipe.

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Craftsmanship Expectations for Welding Projects

The student should complete the following tasks prior to welding.

1. Thoroughly read each drawing.

2. Make a cutting list for each project. Cut at least two project's worth of

metal at a time, this will save a great amount of time.

3. Assemble the welding projects per drawing specifications.

4. Review Welding Procedure portion of the prints to review welding

parameter information.

5. See the instructor for the evaluation.

Factors for grading welding projects are based on the following criteria:

Metal Preparation Project Layout Post Weld Clean-up

Oxyfuel cut quality Accurate (+/- 1/16”) Remove Slag/Spatter

Grind all cut surfaces clean Limit waste Remove sharp edges

Student Assessment piece completed

Weld Quality per ASME Section IX and AWS D1.1

VT Criteria Root Pass Cover Pass

Reinforcement Flush to 1/16” Flush to 1/8”

Undercut 1/32 “ deep 1/32” deep

Bead Contour Smooth Transition Smooth Transition

Penetration Complete Joint Penetration N/A

Cracks None Allowed None Allowed

Arc Strikes None Allowed None Allowed

Fusion Complete Fusion Required Complete Fusion Required

Porosity None Allowed None Allowed

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E6010/E7018 Butt Joint- Single Vee (6G) Project #1 Welding Sequence

E6010-- Root Pass Utilize the "key hole" technique

E6010-- Hot Pass Increase amperage 10 to 20 amps above root bead setting. Use the

whip and pause technique to “Paint the walls” to burn out wagon

tracks.

E7018-- Fill and Cap Keep a tight arc length when welding- No Whipping. Use

the slant loop oscillation technique.

________________________________________________________________________



Reinforcement

Undercut

Bead Contour

Penetration N/A

Cracks

Arc Strikes

Fusion

Porosity

Grade and Date

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E6010/7018 Butt Joint- Single Vee (5G) Project #2 Welding Sequence

E6010-- Root Pass Utilize the "key hole" technique

E6010-- Hot Pass Increase amperage 10 to 20 amps above root bead setting. Use the

whip and pause technique to “Paint the walls” to burn out wagon

tracks.

E7018-- Fill and Cap Keep a tight arc length when welding- No Whipping. Use

the side-to-side or circular weave technique.

________________________________________________________________________



Reinforcement

Undercut

Bead Contour

Penetration N/A

Cracks

Arc Strikes

Fusion

Porosity

Grade and Date

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Final Exam

Part One

This portion of the final exam is a closed book test. Consult with your instructor to

determine items that you may need to review. Once you determine that you are ready for

the exam, request it from your instructor. Complete the exam and write all answers on

the answer sheet. Once completed, return the exam and the answer sheet to your

instructor.

Study Guide

Safety

• Oxyacetylene safety

• SMAW safety

• Hand Tool Safety

SMAW and OAC Processes

• Power source specifics

o Polarity

o Current out put

• AWS electrode classification

• OAC

o Theory of cutting

o Flame types

Welding Symbols and Blueprints

• Orthographic views

• Isometric views

• Welding symbol

o Weld symbols

o Reference line

o Tail

Math and Math conversions

� Adding and subtracting fractions

� Reading a tape measure

� Metric conversions

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WLD 257 Answer Sheet

Name: _____________________________________ Date: ___________________

1.

11.

2.

12.

3.

13.

4.

14.

5.

15.

6.

16.

7.

17.

8.

18.

9.

19.

10.

20.

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Part Two

This portion of the exam is a practical test where you will fabricate and weld a weldment

from a blue print. The evaluation of this portion of the exam will be based on quality.

Once completed, return the print with the weldment to the instructor for grading.

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Welding Procedure Specification for the Final Exam

WPS PCC-SMA-P-98

Supporting PQR Revision Date

PQR-PCC-SMA-P-98 1 9-9-98

Welding Process Type

Shielded Metal Arc Welding Manual

Base Metal Position and Progression

Material Spec. SA 53 6G vertical up

Type or Grade A or B

Thickness Sch 80

Diameter (pipe) 6” nominal

Filler Metal Specification Gas

SFA 5.1 & SFA 5.5 N/A

Filler Metal Classification

E6010- root pass and hot pass

E7018- fill and cap

Technique Electrical Characteristics

E6010 - Whip and Pause DCEP

E7018 - Circular oscillation (Weave/Stringer) DCEP

Electrode Voltage Range Amperage Range

E6010 1/8” 21 - 24 V.D.C. 90 - 135 Amps

E7018 3/32” 21 - 24 V.D.C. 70 - 100 Amps

Post Weld Heat Treatment Preheat

None None

Cleaning

Grind as required ensuring not to damage pipe wall. All slag shall be removed

prior to welding the next bead. _____________________________________________________________________________________

See attached drawing for further specifications.

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Grading Traveler for the WLD 257 Practical Exam

Name:________________________________ Date______________________

Hold Points are mandatory points in the fabrication process, which require the

inspector to check your work. You will have the following hold points that you

instructor will check

Points

Possible

Hold Points Instructor’s

Evaluation

5 points Blueprint Interpretation and Material Cut List 5 points = 0 errors, all parts labeled and sized correctly

3 points = 1 error in part sizing and/or identification

2 points = 2 errors or more rework required (max points)

10 Points Using the orthographic drawing convert it to an isometric

sketch

10 points Material Layout and Cutting (Tolerances +/- 1/16”) 10 points

Layout and cutting to +/-1/16”

Smoothness of cut edge to 1/32”

7 points

Layout and cutting to +/- 1/8” Smoothness of cut edge to

1/16”

5 points (Rework required max points)

Layout and cutting to +/-3/16”

Smoothness of cut edge to 3/32”

10 points Fit-up and Tack weld (Tolerances +/- 1/16”) 10 points

Tolerances +/- 1/16”

Straight and square to +/-1/16”

7 Points



5 Points (Rework required - Max points)



15 points Weld Quality

Subtract 1 point for each weld discontinuity,

incorrect weld size and incorrect spacing sequence.

35 points Minimum points acceptable. This equates to the minimum

AWS D1.1 Code requirements.

Total Points /50

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WLD 257 Isometric Drawing

Name: ________________________________ Date: __________________

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Final Grades - WLD 257 Name: _________________ Instructor: ___________________ Date: __________________

Welding Projects = 40%

Out of Out of Out of






A Total Project pts. ________ / Total pts. Possible _______ X 40 = _______ %

Written Work = 20%




B. Total Project pts. ________ / Total pts. Possible _______ X 20 = _______ %

Safety = 15% Each day of attendance is worth 3 points earned. Any safety violation will result in 0 points

for the day.

Out of Out of Out of Out of Out of Out of



C Total pts. earned ________ / Total pts. Possible _______ X 15 = _______ %

Employability Skills = 15% The following attributes will be assessed - attendance, attitude, time

management, team work, interpersonal skills, etc.. Daily points (there are no excused absences, hence no

points earned for days missed ) 3 pts = present and working for the entire shift; 2 pts = late; 1 pt = late and

left early; 0 pts = no show.




D Total pts. earned ________ / Total pts. Possible _______ X 15 = _______ %

Final Exam 10%

Written Exam Out of

Practical Exam Out of

E Total Project pts. ________ / Total pts. Possible _______ X 10 = _______ %

Add Lines A + B + C + D +E. This will give you your Final Grade TOTAL % _________

FINAL GRADE _________

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