Welding Inspection Company
This article provides you with information about services of the welding inspection company for industrial equipment, steel structure, above ground storage tank, process and power piping systems.
We conduct our welding inspection services in
three stages as below:
Stage 1 - Tasks Prior to Welding Work
We as welding inspection Agency make sure that:
- 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
- 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.
- 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
- 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
- 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
- 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
- Preheat equipment and technique are
- Preheat coverage and temperature are correct.
- Reheat, if required, applied to thermal
- Preheat, if required, applied to remove
- Filler metal type and size are correct
- Filler metals are being properly handled
- Filler metals are clean and free of
- 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
- Shielding gas and purging manifold
systems are periodically bled to prevent back filling with air.
We as welding inspection company utilize many instruction, procedures, welding inspection forms to check above point precisely that refer to inspection activities that are done before welding process.
Stage 2 - Tasks during Welding Operations
We as welding inspection company make sure that:
- 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
- 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
- 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
- Tack welds to be incorporated in the weld are of
- Weld root has adequate penetration and quality.
- Cleaning between weld passes and of any back-gouged surfaces
- 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.
We as welding inspection company utilize many instruction, procedures, welding inspection forms to check above point precisely that refer to the inspection activities during welding process.
Stage 3 - Tasks Upon Completion Of Welding
We as welding inspection company make sure that:
- 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
- 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
- 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
- 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
- Inspection reports, NDE examiners interpretations and findings are
We as welding inspection company utilize many instruction, procedures, welding inspection forms to check above point precisely that refer to inspection after welding process.
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.
qualifications give suitability of weld for required mechanical properties
(i.e., strength, ductility), while performance qualifications show ability of
the welder to deposit sound weld. This must be checked by welding inspection company.
- WPS and PQR made
in accordance with requirement of sec IX prior to 1962 in which all requirement
of 1962 edition are met may also be used
- Each manufacture
or contractor shall maintain a record of the result obtained in welding
procedure and welder/operator performance qualifications. The records shall be
certified by manufacture or contractor and accessible to the authorized
- 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 job.
represent parent metal classification of similar composition and properties,
i.e., similar strength and ductility.
give similar usability aspects of filler material.
give similar chem. comp. In“as welded” condition.
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.
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 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 validity of PQR.
- Only in SMAW,
SAW, GTAW, PAW and GMAW (except short-circuiting) or combination of them
Radiography test can be used for welder performance qualification test, but
there is 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
- For welder
performance qualification when 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 examiner for mechanical, in a similar way if
mechanical test coupon has failed, two test coupons shall make by welder, both
test coupon shall pass the test.
- For welder
performance qualification by radiography for immediate retest, two 6 inch plate
and for 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 specific paragraph in this article, in similar way for welder
performance qualification in QW-352 through 356 should only to refer to
- For performance,
1G is flat, 2G is horizontal, 3G is vertical and 4G is overhead position. Pipe
5G qualifies 1G, 3G and 4G, but pipe 6G qualifies all positions.
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