What Is PQR?

A PQR (Procedure Qualification Record) is the factual record of a test weld made under controlled conditions to prove that a Welding Procedure Specification (WPS) produces welds with acceptable mechanical properties. The PQR documents the actual welding variables used during the test and the results of destructive testing performed on specimens extracted from the test coupon.

PQR Qualification Process

The sequence follows ASME Section IX, Article II (QW-200):

1. Draft a preliminary WPS with the intended welding variables
2. Weld a test coupon (plate or pipe) following the draft WPS under the supervision of a qualified inspector
3. Record all actual variables used during welding (amperage, voltage, travel speed, heat input)
4. Extract test specimens from the welded coupon per QW-462 and QW-463
5. Perform destructive testing (tensile, bend, impact, hardness as required)
6. Document results on the PQR form (QW-483)
7. If all tests pass, the PQR supports the WPS as qualified

Required Mechanical Tests

Test	ASME Section IX Reference	Acceptance Criteria
Transverse tensile	QW-150, QW-462.1	Tensile strength >= base metal minimum or specified minimum
Guided bend (root & face)	QW-160, QW-462.2	No open defects > 3 mm (1/8”) in any direction
Side bend (thickness > 10 mm)	QW-160, QW-462.2	No open defects > 3 mm (1/8”) in any direction
Charpy impact (when required)	QW-170, supplementary essential	Meet minimum energy and lateral expansion per code
Macro examination (fillets)	QW-183	Sound weld, fusion to root, no cracks
Hardness (sour service)	Per NACE MR0175	Max 22 HRC in weld metal, HAZ, and base metal

PQR vs WPS: Key Differences

Aspect	WPS	PQR
Purpose	Instruction to the welder	Record of qualification test
Content	Ranges of variables (min/max)	Actual single values used
Variables	Essential + supplementary essential + non-essential	Essential + supplementary essential only
Revision	Non-essential variables can be revised freely	Cannot be revised (factual record)
Quantity	Multiple WPS can reference one PQR	One PQR supports one or more WPS

Common Mistake

A PQR is a factual record of what was done and what the tests showed. It must never be altered or “updated” after the fact. If test results are unacceptable, the coupon must be re-welded and re-tested; a new PQR is created; the failed PQR is retained but not used for qualification.

Thickness and Diameter Qualification Ranges

The test coupon thickness determines the qualified WPS thickness range per QW-451:

Test Coupon Thickness (T)	Qualified Min Thickness	Qualified Max Thickness
Less than 1.5 mm	T	2T
1.5 mm to 10 mm	1.5 mm	2T
Over 10 mm but < 38 mm	5 mm	2T
38 mm and over	5 mm	200 mm (8”)

PQR records are reviewed during pipe inspections and third-party audits. Together with the WPS and WPQ, they form the complete welding qualification package required for fabrication of piping per ASME B31.3 and B31.1.

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