Should the lab tell me pass or fail?

The lab reports test data. Pass/fail determination is the welding engineer's or CWI's call against the code's acceptance criteria. A reputable lab will note when a result falls below code minimums, but the formal pass/fail signature comes from the responsible engineer.

What if the lab report and the witness data don't match?

Investigate. Discrepancies usually point to a coupon identification mix-up or a typo in the witness log. Address the discrepancy before signing the PQR — an inconsistency on file is an audit failure waiting to happen.

Does the lab need to be accredited?

Yes. AWS D1.1 expects testing to be performed by labs accredited per A2LA, IAS, NVLAP, or equivalent ISO/IEC 17025 program. Always include the lab's accreditation certificate in the PQR file.

Reading a PQR test report: what inspectors look for

A PQR lab report is densely formatted. Here's the five-minute read that experienced CWIs use to spot problems — and confirm the PQR actually supports the WPS.

A PQR lab report can be five pages of small print, formal tables, and unfamiliar acronyms. Experienced CWIs read them in five minutes by hitting these checkpoints in order.

1. Identification block

First check: does the report reference the right PQR number and the right test coupon ID? Labs handle hundreds of coupons per month. A mix-up in identification is rare but expensive.

What to verify:

PQR number on the report matches your filed witness log
Coupon ID matches the one stamped on the coupon
Lab name, accreditation number, and address
Report date and reference number

2. Tensile results

Two numbers per specimen:

Cross-sectional area — measured by the lab, used to compute UTS
Ultimate Tensile Strength (UTS) — peak load divided by area

Compare each specimen's UTS to the base metal's specified minimum tensile from the WPS:

A36 → 58 ksi minimum
A572-50 → 65 ksi minimum
A992 → 65 ksi minimum
A516-70 → 70 ksi minimum

Pass criterion: UTS at or above the base metal minimum. Fracture location is informational, not pass/fail.

Red flags:

UTS below minimum on either specimen
One specimen markedly higher than the other (suggests inconsistent welding)
Fracture in the weld at low UTS (filler/base mismatch or weld defect)

3. Bend results

For each bend specimen (face, root, or side):

Bend angle completed
Discontinuity list — any cracks, openings, or defects on the convex (tension) surface
Maximum dimension of each discontinuity

Pass criterion: no single discontinuity over 1/8 in [3 mm] in any direction on the convex surface. Corner discontinuities (within ~1/8 in of edge) are evaluated separately.

Red flags:

Any discontinuity > 1/8 in
Multiple smaller discontinuities clustered along the bond line (lack of fusion)
A failed bend with the same root cause as another bend on the same coupon

4. CVN results (if applicable)

Three specimens per location. Look for:

Test temperature — must match the code-specified temperature
Energy absorbed for each specimen
Lateral expansion for each specimen (sometimes reported)

Pass criterion: average of three at or above the specified minimum, with no individual specimen below the specified individual minimum.

Red flags:

Any single specimen below the individual minimum
Test temperature different from what the code or contract required
Excessive scatter across the three (suggests inconsistent grain structure or HAZ effects)

5. Macroetch (if performed)

For fillet weld PQRs and some groove configurations:

Cross-section etched
Photographed at marked scale
Examined for fusion, penetration, discontinuities

Pass criterion: complete fusion, no cracks, no incomplete fusion or penetration, slag inclusions within Clause 6 limits.

Red flags:

Visible lack of root fusion
Cracking visible in the etch
Disproportionate HAZ relative to the weld size

6. Accreditation page

Last but not least: confirm the lab is currently accredited. ISO/IEC 17025 accreditation through A2LA, IAS, or NVLAP. The certificate copy belongs in the PQR file.

If the lab's accreditation lapsed during the test period, the PQR is auditable but the auditor may push back.

Compiling into the PQR document

The PQR consolidates:

Witness log (from the welding)
Lab report (from the testing)
Pass/fail determination signed by the welding engineer or CWI
Lab's accreditation certificate

That bundle stays on file for the procedure's lifetime.

Reading a PQR test report: what inspectors look for

1. Identification block

2. Tensile results

3. Bend results

4. CVN results (if applicable)

5. Macroetch (if performed)

6. Accreditation page

Compiling into the PQR document

Frequently asked.