Stage 1 - Welding Inspection Prior to Welding Work
Welding Symbols and weld sizes are specified in drawings 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, was 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 are defined.
Post-weld heat treatment (PWHT) requirements and acceptable PWHT method defined.
Inspection hold-points and NDE requirements defined.
Additional requirements, such as production weld coupons, are 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
The roles and responsibilities of engineers, welding organizations, and welding inspectors are defined and appropriate for the work.
The 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 the 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, and 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 detailed 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 are 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.
The 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, is performed in the procedure.
The 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 are correct and acceptable.
Dimensions of base materials, filler metal, and weld joint are correct.
Piping socket welds have a 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
The 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.
The coating on coated electrodes is neither damaged nor wet.
Flux is appropriate for the welding process and is properly handled.
Inert gases, if required are appropriate for shielding and purging.
The gas composition is correct and meets any purity requirements.
Shielding gas and purging manifold systems are periodically bled to prevent backfilling with air.
Stage 2 - Welding Inspection During Welding
The 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 (a key element in heat input).
Heat input (where appropriate).
Mock-up weldment, if required, meets the requirements of the 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
The size, length, and location of all welds conform to the drawings/specifications / Code.
No welds were 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 were 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 the examiner’s findings.
Specified locations examined.
Specified frequency of examination.
NDE performed after final PWHT.
The work of each welder was included in random examination techniques.
RT film quality, IQI placement, IQI visibility, etc. comply with standards.
The inspector is in agreement with examiner's interpretations and findings.
Documentation for all NDE correctly executed
Verify that 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 are protected from oxidation.
Equipment internals, such as valve internals, were 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 is applied to the component where required for local heating.
Temperature and hold time is correct.
The heating rate and cooling rate are correct.
Distortion is acceptable after the completion of the thermal cycle.
Hardness indicates an acceptable heat treatment
Verify pressure test is performed to the procedure
Pressure meets test specifications.
Test duration is as specified.
The metal temperature of the 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 a welding inspection company utilize many instructions, procedures, and welding inspection forms to check the above point precisely that refers to inspection after the welding process.
Welding Inspection @ ASME Section IX
Here are some important points in the ASME Section IX that are necessary to be taken into account for any Welding Inspection company that conducts welding inspection on fixed equipment, process and power piping, and above-ground storage tanks.
A Welding Procedure Specification is a written document that provides direction to the welder or welding operator for making production weld in accordance with code requirements. It must be checked by a welding inspection company.
The PQR documents what occurred during the welding of the test coupon and the result of the testing of the coupon. It must be checked by a 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 the welding inspection company.
Each manufacturer or contractor shall maintain a record of the result obtained in the welding procedure and welder/operator performance qualifications. The records shall be certified by the manufacturer or contractor and accessible to the authorized inspector
The tension test gives tensile value, while the bend test shows ductility and soundness. Radiography also indicates soundness.
Thus, Procedure Qualification: Tension test + Bend test
Performance Qualification: Bend test or Radiography
The 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 the welding inspection company.
When the welder or welding operator is qualified by radiography, the minimum length of the coupon to be examined shall be 6 inches and shall include the entire weld circumference for the pipe
Production test with some conditions is acceptable
The 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 an impact strength requirement. Otherwise, they are “non-essential” variables.
EV and SEV are included in the PQR document. EV, SEV, and NEV are included in the WPS document.
The PQR document gives data used in the 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 the PQR.
Only in SMAW, SAW, GTAW, PAW, and GMAW (except short-circuiting) or the combination of Radiography Tests 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 coupons for each position which he has failed. If both test coupons pass the visual inspection one may be selected by the examiner for mechanical, in a similar way if the mechanical test coupon has failed, two test coupons shall be made by the welder, and both test coupons shall pass the test.
For welder performance qualification by radiography for the immediate retest, two 6 inch plates and pipe examination shall include two pipes for a total of 12 inches of weld which shall include the entire weld circumference
When the welder has not welded with a process for 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.
References:
1. Inspection 4 Industry
