Welding Inspection Procedure / Checklist

This article provides you a general welding inspection proceduer.

Stage 1 - Welding Inspection Prior to Welding Work

Welding symbols and weld sizes clearly specified in drawing and related documents.
Weld joint designs and dimensions clearly specified in drawings and related documents.
Weld maps identify the welding procedure specification (WPS) to be used for specific weld joints.
Dimensions detailed and potential for distortion addressed.
Welding consumables specified.
Proper handling of consumables, if any, identified.
Base material requirements specified (such as the use of impact tested materials where notch ductility is a requirement in low temperature service).
Mechanical properties and required testing identified.
Weather protection and wind break requirements defined.
Preheat requirements and acceptable preheat methods defined.
Post-weld heat treatment (PWHT) requirements and acceptable PWHT method defined.

I4I Academy provides a variety of welding inspection courses, including those integrated into the API 570 Piping Inspector, API 510 Pressure Vessel Inspector, and API 653 Above-Ground Storage Tank Inspector courses. The API 570 course delves into welding inspection as per API RP 577, API RP 574, and ASME Section IX. Similarly, API 510 course covers related aspects in API RP 572, API RP 577, and ASME Section IX. The API 653 course addresses welding inspection through API RP 575, API RP 577, and ASME Section IX. Additionally, welding inspection is a focal point in three other training courses, namely the ASME IX course, the ASME course, and the API Source Inspector course.

Inspection hold-points and NDE requirements defined.
Additional requirements, such as production weld coupons, clearly specified.
Pressure testing requirements, if any, clearly specified
Competency of welding organization to perform welding activities in accordance with codes, standards, and specifications specified
Roles and responsibilities of engineers, welding organization, and welding inspectors defined and appropriate for the work.
Independence of the inspection organization from the production organization is clear and demonstrated.
WPS(s) are properly qualified and meet applicable codes, standards and specifications for the work.
Procedure qualification records (PQR) are properly performed and support the WPS(s).
Welder performance qualifications (WPQ) meet requirements for the WPS.
NDE examiners are properly certified for the NDE technique.
NDE procedures are current and accurate.
Calibration of NDE equipment is current.
Welding machine calibration is current
Instruments such as ammeters, voltmeters, contact pyrometers, have current calibrations.

Storage ovens for welding consumables operate with automatic heat control and visible temperature indication.
Heat treatment procedure is available and appropriate
Pressure testing procedures are available and detail test requirements.
PWHT equipment calibration is current.
Pressure testing equipment and gauges calibrated and meet appropriate test requirements.
Material test certifications are available and items properly marked (including back-up ring if used ;).
Electrode marking, bare wire flag tags, identification on spools of wire, etc. as-specified.
Filler material markings are traceable to a filler material certification.
Base metal markings are traceable to a material certification.
Recording of filler and base metal traceability information is performed.
Base metal stampings are low stress and not detrimental to the component.
Paint striping color code is correct for the material of construction.
PMI records supplement the material traceability and confirm the material of construction.
Weld preparation surfaces are free of contaminants and base metal defects such as laminations and cracks.
Preheat, if required, applied for thermal cutting c. Hydrogen bake-out heat treatment, if required, performed to procedure.
Weld joint is free from oxide and sulfide scales, hydrocarbon residue, and any excessive build-up of weld-through primers.
Weld joint type, bevel angle, root face and root opening are correct.
Alignment and mismatch is correct and acceptable

Dimensions of base materials, filler metal, and weld joint are correct.
Piping socket welds have proper gap.
Preheat equipment and technique are acceptable.
Preheat coverage and temperature are correct.
Reheat, if required, applied to thermal cutting operations.
Preheat, if required, applied to remove moisture
Filler metal type and size are correct per procedure.
Filler metals are being properly handled and stored.
Filler metals are clean and free of contaminants.
Coating on coated electrodes is neither damaged nor wet.
Flux is appropriate for the welding process and being properly handled.
Inert gases, if required are appropriate for shielding and purging.
Gas composition is correct and meets any purity requirements.
Shielding gas and purging manifold systems are periodically bled to prevent back filling with air.

Stage 2 - Welding Inspection During Welding

Welder is responsible for quality craftsmanship of weldments
Welder meets qualification requirements
Welder understands welding procedure and requirements for the work.
Special training and mock-up weldments performed if required.
Welder understands the inspection hold-points.
Essential variables are being met during welding.
Filler material, fluxes, and inert gas composition/flow rate.
Purge technique, flow rate, O2 analysis, etc.
Rod warmers energized or where rod warmers are not employed, the welder complies with maximum exposure times out of the electrode oven.
Preheating during tack welding and tack welds removed (if required).
Welding technique, weld progression, bead overlap, etc.
Equipment settings such as amps, volts, and wire feed.
Preheat and interpass temperatures.
Travel speed (key element in heat input).
Heat input (where appropriate).
Mock-up weldment, if required, meets requirements with welder and welding engineer.
Welder displays confidence and adheres to good welding practices.
Tack welds to be incorporated in the weld are of acceptable quality.
Weld root has adequate penetration and quality.
Cleaning between weld passes and of any back-gouged surfaces is acceptable.
Additional NDE performed between weld passes and on back-gouged surfaces shows acceptable results.
In-process rework and defect removal is accomplished.
In-process ferrite measurement, if required, is performed and recorded.
Final weld reinforcement and fillet weld size meets work specifications and drawings.

Stage 3 - Welding Inspection Upon Completion Of Welding

Size, length and location of all welds conform to the drawings / specifications / Code.
No welds added without approval.
Dimensional and visual checks of the weld don’t identify welding discontinuities, excessive distortion and poor workmanship.
Temporary attachments and attachment welds removed and blended with base metal.
Discontinuities reviewed against acceptance criteria for defect classification.
PMI of the weld, if required and examiner’s findings indicate they comply with the specification.
Welder stamping/marking of welds confirmed.
Perform field hardness check.
Verify NDE is performed at selected locations and review examiner’s findings.
Specified locations examined.
Specified frequency of examination.
NDE performed after final PWHT.
Work of each welder included in random examination techniques.
RT film quality, IQI placement, IQI visibility, etc. complies with standards.
Inspector is in agreement with examiners interpretations and findings.
Documentation for all NDE correctly executed
Verify post-weld heat treatment is performed to the procedure and produces acceptable results.
Paint marking and other detrimental contamination removed.
Temporary attachments removed.
Machined surfaces protected from oxidation.
Equipment internals, such as valve internals, removed to prevent damage.
Equipment supported to prevent distortion.
Thermocouples fastened properly.
Thermocouples adequately monitor the different temperature zones and thickest/thinnest parts in the fabrication.
Temperature monitoring system calibrated.
Local heating bandwidth is adequate.
Insulation applied to the component where required for local heating.
Temperature and hold time is correct.
Heating rate and cooling rate is correct.

Distortion is acceptable after completion of the thermal cycle.
Hardness indicates an acceptable heat treatment
Verify pressure test is performed to the procedure
Pressure meets test specification.
Test duration is as-specified.
Metal temperature of component meets minimum and maximum requirements.
Pressure drop or decay is acceptable per procedure.
Visual examination does not reveal defects.
Perform a final audit of the inspection dossier to identify inaccuracies and incomplete information.
All verifications in the quality plan were properly executed.
Inspection reports are complete, accepted and signed by responsible parties.
Inspection reports, NDE examiners interpretations and findings are accurate.

We as welding inspection company utilize many instruction, procedures, welding inspection forms to check above point precisely that refer to inspection after welding process.

Welding Inspection @ ASME Section IX

Here are some important points in the ASME Section IX that are necessary to be taken in account for any welding inspection company that conducts welding inspection on fix equipment, process and power piping and above ground storage tank.

A WPS is a written document that provides direction to the welder or welding operator for making production weld in accordance code requirement. It must be check by welding inspection company.
The PQR documents what occurred during welding the test coupon and the result of testing of the coupon. It must be checked by welding inspection company.
Procedure qualifications give suitability of weld for required mechanical properties (i.e., strength, ductility), while performance qualifications show the ability of the welder to deposit sound weld. This must be checked by welding inspection company.
Each manufacturer or contractor shall maintain a record of the result obtained in welding procedure and welder/operator performance qualifications. The records shall be certified by manufacturer or contractor and accessible to the authorized inspector
Tension test gives tensile value, while bend test shows ductility and soundness. Radiography also indicates soundness.
Thus, Procedure Qualification: Tension test + Bend test
Performance Qualification: Bend test or Radiography
Tensile test for procedure qualification is passed if failure is in a)Weld metal at strength>= Base metal SMTS or b)Base metal at strength>= 95% of base metal SMTS. This must be checked by welding inspection company.
When the welder or welding operator is qualified by radiography, the minimum length of coupon to be examined shall be 6 inch and shall include the entire weld circumference for pipe
Production test with some condition is acceptable

Bend test crack shall not exceed 1/8” in any direction. Radiography criteria are stricter than radiography for the job.
P-numbers represent parent metal classification of similar composition and properties, i.e., similar strength and ductility.
F-number gives similar usability aspects of filler material.
A-number gives similar chem. comp. In“as welded” condition.
Essential variables (EV), if changed require new procedure qualification. Non-essential variables (NEV) may be changed without new procedure qualification. But the procedure must be revised.
Supplementary essential variables (SEV) are considered as (EV) only if there is impact strength requirement. Otherwise, they are “non-essential” variables.
EV and SEV are included in PQR document. EV, SEV, and NEV are included in WPS document.
PQR document gives data used in PQR test and test results, and cannot be revised.
WPS gives parameters to be used in the production job and must be within ranges qualified by the PQR test.
WPS may be revised within the EVs qualified. The NEVs can always be revised without affecting the validity of PQR.
Only in SMAW, SAW, GTAW, PAW and GMAW (except short-circuiting) or the combination of them Radiography test can be used for welder performance qualification test, but there is an exception, except P-No.21 through P-No.25 and P-No.51 through P-No.53 and P-No.61 through P-No.62, welder making groove welds P-No.21 through P-No.25 and P-No.51 through P-No.53 metals with GTAW process may also be qualified by radiography.

For welder performance qualification when the coupon has failed the visual examination, and immediate retest is intended to be done, the welder shall make two test coupon for each position which he has failed. If both test coupons passed the visual inspection one may be selected by the examiner for mechanical, in a similar way if mechanical test coupon has failed, two test coupons shall make by the welder, both test coupon shall pass the test.
For welder performance qualification by radiography for immediate retest, two 6 inch plate and pipe examination shall include two pipes for a total of 12 inch of weld which shall include entire weld circumference
When the welder has not welded with a process during a period of 6 months or more, his qualification for that process shall expire
Article IV should not be read directly, during the study of other articles specifically “welding variables procedures specifications” (QW-252 through 265 ) should refer to a specific paragraph in this article.
For performance, 1G is flat, 2G is horizontal, 3G is vertical, and 4G is the overhead position. Pipe 5G qualifies 1G, 3G, and 4G, but pipe 6G qualifies all positions.

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