6.2 Procedure Qualification Record (PQR)
Key Takeaways
- A PQR records the ACTUAL single values welded on a test coupon plus the mechanical test results — it is the objective evidence that qualifies a WPS
- Required D1.1 groove tests: transverse tensile (≥ base-metal min) and guided bend (no open discontinuity > 1/8 in / 3 mm), plus CVN if specified
- Table 6.2: a coupon ≥ 1 in (25 mm) qualifies unlimited production thickness; a thinner coupon qualifies 1/8 in to 2T
- Essential change → new PQR; supplementary essential → new PQR only if CVN testing required; nonessential → revise WPS only
- The CWI confirms each qualified-by-test WPS is backed by a valid PQR and that production thickness is within the PQR's qualified range
What a PQR Is
A Procedure Qualification Record (PQR) is the document that records the actual welding variables used to weld a test coupon and the results of the mechanical tests performed on that coupon. Where the WPS is the recipe written for the future, the PQR is the objective evidence — generated in the past — that proves the recipe works. AWS A3.0 frames it as the record demonstrating that a weldment made by a given procedure meets the prescribed mechanical-property requirements. One PQR (or several together) supports one or more WPSs.
The critical relationship: the PQR qualifies the WPS. A qualified-by-test WPS cannot exist without a PQR behind it. The PQR captures single actual values (e.g., the welder ran exactly 165 A at 24 V, 8 in/min, 250°F preheat), and the WPS then publishes ranges around those proven values.
What the PQR Records
| Information | Detail Captured |
|---|---|
| Actual variables | Exact amperage, voltage, travel speed, preheat, interpass — single values, not ranges |
| Base metal | Actual specification, grade, group/P-number, coupon thickness |
| Filler metal | Actual AWS classification, F-number, A-number, diameter |
| Mechanical test results | Tensile, guided bend, CVN impact (if required), hardness (if required) |
| Witnessing/lab | Testing laboratory, technician, and the responsible signatory |
Required Mechanical Tests (AWS D1.1, CJP Groove)
| Test | What It Proves | Acceptance / Count |
|---|---|---|
| Transverse tensile (×2) | Joint strength | Must equal or exceed the minimum specified tensile of the base metal |
| Root and face guided bend | Soundness (for thinner coupons) | No open discontinuity > 1/8 in (3 mm) in any direction on the convex surface |
| Side bend (×4) | Soundness through full thickness | Used for thicker coupons; same 1/8 in limit |
| CVN impact (if specified) | Notch toughness | Per contract — driven by supplementary essential variables |
The headline acceptance number to memorize: no open discontinuity exceeding 1/8 in (3 mm) in any dimension on the bent convex face. Small base-metal-origin defects are evaluated separately.
Reading Each Test
- Transverse tensile pulls a machined cross-weld specimen to failure. The recorded ultimate tensile strength must meet or exceed the minimum specified tensile of the weaker base metal. Failure in the base metal at or above that value is acceptable.
- Guided bend wraps a specimen around a mandrel (typically to 180°). Root bends stretch the root side, face bends stretch the face side, and side bends stretch the full thickness — side bends are mandatory for thicker coupons because they reveal mid-thickness lack of fusion that surface bends miss.
- CVN (Charpy V-notch) impact is a toughness test run only when the contract invokes it, and is governed by the supplementary essential variables.
Thickness Range a PQR Qualifies (Table 6.2)
A single PQR does not qualify only the exact coupon thickness — it qualifies a range, so one test can cover many production thicknesses.
| Test Coupon Thickness (T) | Production Thickness Qualified |
|---|---|
| 1/8 in (3 mm) ≤ T < 1 in (25 mm) | 1/8 in (3 mm) minimum to 2T maximum |
| T ≥ 1 in (25 mm) | 1/8 in (3 mm) minimum to unlimited |
Thus a 1 in coupon qualifies unlimited production thickness — the single most exam-tested PQR number. Square-groove welds qualified without backgouging are limited to the test thickness.
Essential vs. Nonessential vs. Supplementary Essential
Whether a WPS change forces a new PQR depends on how the changed variable is classified:
| Class | Effect | Change Beyond Range Means |
|---|---|---|
| Essential | Affects mechanical properties (tensile/bend) | Requalify — new PQR required |
| Supplementary essential | Affects notch toughness | New PQR only when CVN impact testing is required |
| Nonessential | No significant property effect | Revise the WPS only — no requalification |
Examples of Each Class
| Class | Representative Variables (AWS D1.1) |
|---|---|
| Essential | Change of process; change of F-number group; deleting or adding PWHT; increase in thickness beyond the qualified range; change of shielding/flux; decrease in preheat below qualified minimum |
| Supplementary essential | Increase in heat input or large change in interpass temperature; uphill ↔ downhill progression; a change affecting cooling rate — all relevant only when CVN is required |
| Nonessential | Minor groove-angle or root-opening change; electrode diameter within range; travel-speed tweak; number of passes; cleaning method |
The distinction is exactly why the WPS and PQR are paired documents: the PQR proves the procedure at specific values, and the essential-variable rules define how far the WPS may stray from those proven values before a fresh PQR is mandatory.
The CWI's Role with the PQR
The CWI verifies that each qualified-by-test WPS is actually backed by a valid PQR, that the PQR's recorded variables logically support the WPS ranges, that the required tests were run and passed, and that the production thickness falls within the PQR's qualified range. A WPS calling for a 1-1/2 in production weld supported only by a 1/2 in coupon PQR (max 1 in) is out of range — a finding the CWI must raise.
Exam trap: Adding or deleting PWHT, or a change in welding process, is an essential change (new PQR). A change that only affects toughness (e.g., a small heat-input increase) is supplementary essential — it only forces requalification if the job specifies CVN testing.
What is the guided-bend test acceptance criterion in an AWS D1.1 procedure qualification?
A PQR test coupon is 1 in (25 mm) thick. What production thickness range does it qualify under AWS D1.1 Table 6.2?
A WPS change affects only notch toughness, and the job does NOT require CVN impact testing. How is this change classified and what is required?