9 practical cswip 3.0 practical visual inspection.pdf

THE WELDING INSTITUTE

Welding Inspection of Steels WIS 5Section 23 Practical Visual InspectionRev 30-03-07 Copyright 2007 TWI Middle East

23. 1 WORLD CENTRE FORMATERIALS JOININGTECHNOLOGY

Practical Visual Inspection: (Prepared for CSWIP 3.0 Examination)The CSWIP (Certification Scheme for Welding & Inspection Personnel) examinationscheme for welding inspectors consists at present of the following categories:

CSWIP 3.0 Visual Welding Inspector

CSWIP 3.1 Welding Inspector

CSWIP 3.2 Senior Welding Inspector

The CSWIP 3.0 3.1 and AWS CWI CSWIP 3.1 Bridge examination contents andrespective timings are given below:

Exam Time

CSWIP 3.0Practical butt welded butt joint in plate (Code provided) 1hour 45 minutes.

Practical fillet welded T joint in plate (Code provided) 1hour 15 minutes.

Total time: 3 hours

CSWIP 3.1

Practical butt welded butt joint in plate (Code provided) 1hour 15 minutes.

Practical butt welded butt joint in pipe (Nominated code*) 1hour 45 minutes.

Practical assessment of 2 macros (Code provided) 45 minutes.

Theory Specific. (4 from 6 narrative questions) 1 hour 15 minutes.

Theory General. (30 Multi choice questions) 30 minutes.

Oral. (Questions on code and general inspection) 15 minutes.

Total time: 5 hours 45 minutes

* Nominated code is supplied by the candidate

AWS CWI CSWIP 3.1 Bridge

Practical butt welded butt joint in pipe (Code provided) 1hour 45 minutes.

Practical assessment of 1 macro (Code provided) 25 minutes.

Theory Specific. (1 long + 9 short narrative questions) 1 hour 20 minutes.

Total time: 3 hours 30 minutes




Conditions for Visual Inspection:

The conditions for visual inspection can are affected mainly by the following:1) Lighting.

2) Angle and distance of viewing.

Light: It is essential that there is adequate illumination (lighting) present duringinspection and that the access and angle of viewing are suitable. BS EN 970 states thatthe minimum light conditions shall be 350 lux, but recommends 500 lux (similar tonormal shop or office lighting). 500 lux is also the accepted minimum light level forCSWIP Welding Inspection examinations.

Angle and Distance: BS EN 970 also states that viewing conditions for direct inspectionshall be within 600mm of the surface and the viewing angle (line from eye to surface) tobe not less than 30

It will be fairly obvious that increasing distance from an object will impair the ability toidentify smaller areas of interest with any clarity, though it can also occur that too close adistance can detract from the overall picture of the weld. For general visual inspection ofwelds there is generally an optimum viewing range of 150 500 mm where inspectioncan comfortably be carried out. Optical viewing devices such as magnifying lenses maybe used during inspection to aid observation though the level of magnification allowableis generally given in the applied standard. In BS EN 970 the limits are set from 2x 5xmagnification.

It should also be remembered that it is very good practice to carry out visual inspectionusing a variety of viewing angles as some imperfections particularly mechanical damagecan only be identified when viewed in reflected light.

This can be most easily seen when using the plastics training replicas supplied during thecourse and the CSWIP practical examination where it is advisable to view all surfaces inreflected light, as it is often difficult to observe slight mechanical damage such as lightgrinding marks, or a slightly corroded surface when viewing only at 90

Effective viewing range

600 mm max30




For a candidate to make a respectable attempt at any practical inspection parts of hisCSWIP examination he/she will need to be in possession of a number of important itemsat the exam the venue:

1) Good close vision acuity. (Keen eyesight)

2) Specialist Gauges and useful hand tools i.e. Torch, mirror, graduated scale etc

3) Nominated Specification if applicable. Pencil/pen, and a watch

4) All examination report forms for the practical exams i.e. Macro/Pipe/Plate(Supplied to the candidate by the CSWIP exam invigilator)

1) Good Close Vision Acuity

To effectively carry out visual inspection a qualified CSWIP 3.1 Welding Inspectorshould possess close vision acuity of an acceptable minimum level, thus a test certificateof close vision acuity must be provided before examination in any CSWIP WeldingInspection, or NDT subject. It is also sometimes very important for an inspector todistinguish between contrasting colours in order to effectively interpret results of colourcontrast penetrant, fluorescent penetrant and fluorescent magnetic particle inspectiontests. Therefore all candidates for CSWIP examinations must also submit a colourblindness test certificate for the effected colours. Any vision certification dated over 6months previous to the exam date will not be acceptable to the CSWIP managementboard as any proof of the welding inspectors current vision abilities. All inspectorsshould be aware of the sudden decay of human visual abilities and should make everyeffort to attend a vision test at least twice yearly. Inspectors who use optical devicesshould regularly check that their aided eyesight has not further deteriorated below limits.

2) Specialist Gauges

A number of specialist gauges are available to measure the various elements that need tobe measured in a welded fabrication including:

a) Hi Lo gauges, for measuring mismatch between pipe walls.b) Fillet weld profile gauges, for measuring fillet weld face profile and sizes.c) Angle gauges, for measuring weld preparation angles.d) Multi functional weld gauges, used to measure many weld values. Pages 23.4/ 23.5

Types of gauges, their measuring ranges and accuracy are also detailed in BS EN 970

3) Nominated Specification

All specifications required for the CSWIP 3.0 Visual Welding Inspector examination aresupplied by the examining centre. This is similar in style to specification TWI 09-09-06found on page 23.7 and included for the purposes of practical inspection practice.




THE TWI CAMBRIDGE MULTI-PURPOSE WELDING GAUGE

A tool used in the close estimation of weld dimensions (Accuracy limitations)

Linear and radial scales are given in mm and inches, with angels measured in degrees.

Excess weld metal can be readily calculated by measuring the Leg Length, thenmultiplying by 0.7

This value is subtracted from the measured Throat Thickness = Excess Weld Metal.

Example: For a measured Leg Length of 10mm and Throat Thickness of 8 mm

10 x 0.7 = 7 8 7 = 1 mm of Excess Weld Metal.

Fillet Weld Actual Throat ThicknessThe small sliding pointer reads up to20mm, or inch. When measuring thethroat it is supposed that the fillet weld hasa nominal design throat thickness, aseffective design throat thickness cannotbe measured in this manner.

Angle of PreparationThis scale reads 00 to 600 in 50 steps.The angle is read against the chamferededge of the plate or pipe.

Adjusting screws. Linear scale (Root face/gap) Radial Scale. Linear Scale (Fillet throat)


WeldinSectionRev 30

Linear Misalignment

Fillet Weld Leg LengthThe gauge may be used to measure filletweld leg lengths < 25mm as shown.The gauge may be used to measuremisalignment of members by placing theedge of the gauge on the lower memberand rotating the segment until the pointedfinger contacts the higher member.g Inspection of Steels WIS 523 Practical Visual Inspection

-03-07 Copyright 2007 TWI Middle East


Fillet weld leg length size & profile gauge

Excess Weld Metal/Root penetrationThe scale is used to measure excess weld metalheight or root penetration bead height of singlesided butt welds, by placing the edge of thegauge on the plate and rotating the segment untilthe pointed finger contacts the excess weldmetal or root bead at its highest point.

UndercutThe gauge may be used to measure undercut byplacing the edge of the gauge on the plate androtating the segment until the pointed fingercontacts the furthest depth of the undercut.The reading is taken in the - scale (left of zero)in mm or inches.

Magnification

Gauge: Fillet WeldLeg Length: 10 mmProfile: Mitre.




4) Visual Examination Report Forms

The requirement for examination records/inspection reports will vary according tocontract and type of fabrication and there may not always be a need for a formal record.When a record is required it may be necessary to show that items have been checked atthe specified stages and that they have satisfied the acceptance criteria. The form of thisrecord will vary; possibly a signature against an activity on an Inspection Check List orQuality Plan or an individual report for an item. For individual inspection reports, BS EN970 lists typical details for inclusion as:

a) Name of the component manufacturer b) Examining body, if differentc) Identification of the object examined d) Materiale) Type of joint f) Material thicknessg) Welding process h) Acceptance criteriai) Imperfections exceeding the acceptance criteria and their locationj) Extent of examination with reference to drawings as appropriatek) Examination devices usedl) Result of examination with reference to acceptance criteriam) Name of examiner/inspector and date of examination.

When it is required by contract to produce and retain permanent visual records of a weldas examined, photographs, accurate sketches, or both should be made with anyimperfections clearly indicated. In the Visual Welding Inspector examination assessmentof welds is made using a number of forms. For the T Joint examination 2 sheets(normally 1x double sided page) For the Plate Inspection 3 sheets are issued (normally 1x double and 1x single sided) Acceptance code similar to page 23.7 is provided for exam.

T Joint 1 of 2: Details of all weld measurements and calculated acceptance criteria, thenan acceptance/rejection of the weld dimensions based on calculations.

T Joint 2 of 2: A dimensioned list of observable imperfections and evaluation to thesupplied code and final overall assessment of the fillet welded T joint.

Plate 1 of 3: Details of weld and a dimensioned sketch of imperfections found withinplate weld face area.

Plate 2 of 3: A dimensioned sketch of imperfections found within the plate weld rootarea. Note: Inspection should include surface areas of the plates on weldface and weld root side only and any observations recorded on therelevant sheet. Inspection should always be made from edge to edge.

Plate 3 of 3: A final report form containing all relevant information from sheets 1& 2,then a comparative assessment of the recorded imperfections with thesupplied acceptance criteria. Any additional comments should be madeof the reverse side of this sheet as directed.All information (other than sketches) should be completed in ink only.


Pages 23.9 23.13 contain examples of completed inspection forms used, using the set ofacceptance criteria given below. These acceptance criteria have also been provided forevaluation of the Fillet Welded T Joint and Butt Welded Butt Joint inspection practice.WIS 5 Acceptance LevelsButt Welded Plate & Fillet Welded T Joint Inspection Practice

Specification Number TWI 09-09-06

All dimensions are given in millimetres

Key: = diameter. t = plate thickness. d = depth. h = height

For Training Purposes Only

No Imperfection Comments Allowance1 Cracks Confirm with penetrant testing Not permitted2 Porosity Individual gas pore Maximum 1mmWelding Inspection of Steels WIS 5Section 23 Practical Visual InspectionRev 30-03-07 Copyright 2007 TWI Middle East


3 Solid Inclusions Non-metallic. Individual size Maximum 1mm4 Solid Inclusions Metallic. Not permitted5 Lack of Fusion Sidewall/Root/Inter-run Not permitted6 Incomplete Root Penetration Not permitted7 Overlap/Cold lap Weld face/Root Not permitted8 Incompletely filled groove Not permitted9 Linear Misalignment 0.2t Maximum 4mm10 Angular Misalignment Maximum 1011 Undercut Smoothly blended 10%t Maximum d 1mm12 Arc Strikes Test for cracks using MPI Seek advice for repair13 Laminations Not permitted14 Mechanical Damage Surfaces shall be free of all rust/scale Not permitted15 Cap Height Shall not fall below plate surface Maximum h 3mm16 Penetration Bead Burn-through not permitted Maximum h 2mm17 Spatter Clean & Re-inspect Refer to manufacturer18 Weld Appearance All toes shall blend smoothly Regular along the length19 Root concavity 10%t Maximum d 1mm




Fillet Welded T Joint Practical Exam

1) Firstly, the plate reference number must be recorded in the top left hand corner of thereport sheet, then thickness of the plate is measured and then entered in the top righthand corner of the report sheet in the boxes provided.

2) Secondly, both fillet weld leg lengths must be measured to find both maximum andminimum leg lengths in both Vertical and Horizontal legs. These values are entered inthe boxes provided on the report sheet. Use the gauge as shown below:

3) Thirdly, the maximum and minimum throat thickness is measured and entered in theboxes provided on the report sheet. These values are measured as shown below:

4) Having made all the above measurements they can be assessed to a set of acceptancevalues that may be simply calculated from the known plate thickness.

a) The minimum leg length size is the plate thicknessb) The maximum leg length size is the plate thickness + 3mmc) The minimum throat thickness is the plate thickness x 0.7d) The maximum throat thickness is the plate thickness + 0.5mm

For example if the plate thickness is 6mm then the following will apply:

a) The minimum leg length size is 6mm (Plate thickness)b) The maximum leg length size is the 9mm (Plate thickness + 3mm)c) The minimum throat thickness is the 4.2mm (Plate thickness x 0.7)d) The maximum throat thickness is the 6.5mm (Plate thickness + 0.5mm

All measurements taken must fall within the 2 tolerances calculated i.e. Leg lengthsbetween 6mm 9mm and throat thickness between 4.2 and 6.5mm If any of thevalues are within these tolerances they are acceptable. If any of the values fall outsideof the calculated tolerances then it becomes unacceptable. It should be rememberedthat any change in thickness changes these acceptance values.

Inspect only faces A B and C

Actual Throat ThicknessLowest throat measurement 4.5mmHighest throat measurement 8mm

Vertical Leg LengthLowest leg measurement 7mmHighest leg measurement 8mm

Horizontal Leg LengthLowest leg measurement 5mmHighest leg measurement 10mm

F 123

6mm

AB

C




When completing the report sheet from the sample weld given it should appear as follows:

Example Fillet Welded T Joint Report Sheet

Specimen Number F123 Material thickness: 6mm

1) Measure and record the following details:

VERTICAL LEG LENGTH (Max & Min) = Max 8 mm Min 7 mmHORIZONTAL LEG LENGTH ( ) = Max 10 mm Min 5 mmACTUALTHROAT THICKNESS ( ) = Max 8 mm Min 4.5 mm

2) Sentence the fillet weld dimensions using the following design criteria:

MINIMUM LEG LENGTH: Material thickness (6mm)MAXIMUM LEG LENGTH: Material thickness + 3mm (9 mm)

MINIMUM THROAT THICKNESS: Material thickness x 0.7 (4.2 mm)MAXIMUM THROAT THICKNESS: Material thickness + 0.5mm (6.5 mm)

The VERTICAL LEG LENGTH ACCEPT or REJECT:

Please state: ACCEPT.

The HORIZONTAL LEG LENGTH ACCEPT or REJECT:

Please state: REJECT.

The THROAT THICKNESS ACCEPT or REJECT:

Please state: REJECT

Having assessed the weld for its size an inspection can then be made on the surface tolocate any imperfections. Firstly; the report sheet requests the inspector to indicate thenumber of locations that the following imperfections occur, if any?

3) The number of places that they occur should now be entered in the box as follows:

UNDERCUT APPEAR? 3 placesOVERLAP APPEAR? NoneLACK OF FUSION APPEAR? NoneCRACKS APPEAR? NonePOROSITY APPEAR? 2 AreasSOLID INCULSIONS? 1 Slag InclusionMISC: [ARC STRIKES etc] Spatter




4) For the defects recorded state the MAXIMUM length (and DEPTH ifapplicable) of each defect

UNDERCUT: Length: 15 mm Depth: 1.5 mm (Sharp)

OVERLAP: Length: -------- Depth: ---------

LACK OF FUSION: Length: -------- Depth: ---------

CRACKS: Length: -------- Depth: ---------

POROSITY: Length: 1.5 mm Depth: N/A

SOLID INCLUSIONS: Length: 4mm Depth: N/A

MISC: [ARC STRIKES etc] Length: Spatter Depth: N/A

5) Then, using the code provided assess the levels of imperfections with theallowance in the code as follows:

UNDERCUT: REJECT (Accept or Reject?)OVERLAP: ACCEPT (Accept or Reject?)LACK OF FUSION: ACCEPT (Accept or Reject?)CRACKS: ACCEPT (Accept or Reject?)POROSITY: REJECT (Accept or Reject?)SOLID INCLUSION: REJECT (Accept or Reject?)MISC: [ARC STRIKES etc] REJECT** (Accept or Reject?)

** All spatters should have been removed prior to submission for inspection.Clean then re-submit for inspection.

6) Finally accept or reject the weld used for your visual inspection as follows:

IS THE WELD ACCEPTABLE? NO YES/NO

Signature: I C Plenty

Name: I C Plenty

Date: 30-03-07

This completes the practical Fillet Welded T Joint Inspection Assessment.




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Weld Report Sheet: Page 3 of 3

EXAMPLE WELD INSPECTION REPORT/SENTENCE SHEET

PRINT FULL NAMESPECIMEN NUMBER

Face DefectsEXTERNAL DEFECTS Defects Noted Code or Specification Reference

Defect Type

1

AccumulativeTotal

2

MaximumAllowance

3

Section/Table No

4

Accept/Reject

5Reinforcement (Height) 4 mm 3 mm 15 RejectReinforcement (Appearance) Poor toe blend Smooth toe blend 18 RejectIncomplete filling 22 mm Not permitted 8 RejectSlag Inclusions 8 mm long 1 mm 3 RejectUndercut 1.5 mm depth 1 mm 11 RejectSurface Porosity 1.5 mm 1 mm 2 RejectCracks 40 mm Not permitted 1 Reject +Lack of fusion 22 mm Not permitted 5 RejectArc strikes 30 mm x 25 mm Test with MPI 12 Seek advice +++Mechanical damage NONE --------------------------- ------------- AcceptMisalignment 2 mm (Linear) 0.2 t = 2mm 9 Accept

Root DefectsMisalignment 2 mm (Linear) 0.2 t = 2mm 9 AcceptPenetration (Height) 4 mm 2 mm 16 RejectIncomplete Root Penetration 50 mm Not permitted 6 RejectLack of Root Fusion 70 mm Not permitted 5 RejectRoot Concavity 2 mm depth 1 mm max 19 RejectRoot Undercut NONE ---------------------- ------------- AcceptCracks NONE --------------------------- ------------- AcceptMechanical damage 50 mm x 20 mm Not permitted 14 RejectPorosity NONE ---------------------- ------------- AcceptBurn-through 10 mm length Not permitted 16 Reject

This * pipe/plate has been examined to the requirements of code/specification .............................and is * accepted/rejected accordingly.

Signature......................................................... Date.....................................................

*Delete which is not applicable. Use the other side for any comments.

Comments:

+ Request Penetrant NDT testing to confirm crack and true length.++ Large amount of spatter on weld face. Recommend cleaning, then re-inspection.+++ Recommend arc strikes are ground flush prior to MPI testing for crack detection.

Seek advice on repair upon test results.

This completes the practical Butt Welded Plate Butt Joint Inspection Assessment.

I C Plenty

001

TWI 09-09-06

30th March 2007I C Plenty

9 practical cswip 3.0 practical visual inspection.pdf

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