The Procedure Qualification Record is the documentary foundation of every qualified welding procedure in ASME-governed fabrication. Without a valid PQR, a Welding Procedure Specification cannot be certified; without a certified WPS, production welding on pressure-retaining components cannot legally begin. Yet despite its absolute centrality to fabrication compliance, the PQR is one of the most frequently incorrectly prepared, incompletely filled, and poorly understood documents in welding quality management.

In a typical ASME Section VIII pressure vessel fabrication contract, a welding quality audit will review the PQR package for every WPS used on the job. What auditors find — with surprising regularity — are PQRs with blank mechanical test fields, missing Charpy values for notch-toughness-required service, heat input not calculated, PWHT temperature ranges transcribed incorrectly from the WPS, and certifying signatures from individuals not authorised to certify on behalf of the manufacturer. Any of these deficiencies can result in the rejection of the entire procedure package and the requirement to re-qualify — halting fabrication, generating non-conformance reports, and triggering the schedule and cost consequences that follow.

This guide covers everything: the precise legal and technical relationship between the PQR and WPS, every field on the ASME QW-483 PQR form explained with the correct entry, all mechanical test requirements with acceptance criteria, the essential variable system and how it links PQR qualification to WPS range limits, and a comprehensive list of common PQR errors with their consequences and corrections. For the parallel WPS guide, see our complete WPS guide.

PQR vs WPS — The Fundamental Relationship QW-200

The relationship between the PQR and WPS is one of evidence and application: the PQR is the evidence; the WPS is the application of what the evidence demonstrates. Understanding this distinction is essential for correctly preparing and reviewing both documents.

The practical consequence of this relationship is direct: if an engineer wants to add a new position to an existing WPS, or extend the qualified thickness range, they must first check whether a supporting PQR already demonstrates that position or thickness. If not, a new qualification coupon must be welded, tested, and a new PQR prepared before the WPS can be revised. The PQR drives everything — the WPS cannot assert capabilities that no PQR has demonstrated.

Who Qualifies the Procedure and Who Certifies the PQR QW-103, QW-200.1

The manufacturer or contractor is responsible for qualifying the welding procedure and certifying the PQR. “Manufacturer” in ASME terminology means any organisation that constructs, repairs, or alters pressure equipment under an ASME stamp — it does not mean the raw material manufacturer. The certifying signature on the PQR must be from a person legally authorised to sign on behalf of the manufacturer organisation.

The Welder’s Role — Identified, Not Certifying

The welder who welded the qualification test coupon must be identified on the PQR by name and individual welder identification number (stamp number or ID code). However, the welder does not certify the PQR and does not own it. The PQR belongs to the manufacturer. The welder’s personal qualification is documented separately on a Welder Performance Qualification Record (WPQR or WPQ Test Record), which is a different document. A common error is confusing the welder’s qualification record with the procedure qualification record — they are entirely separate documents with separate content, format, and purpose.

The Authorised Inspector’s Role

The ASME Code Authorised Inspector (AI) does not certify the PQR, but has a specific role in the qualification process: the AI must have the opportunity to witness the welding and testing of the qualification test coupon. In practice, this means the AI must be notified in advance of the qualification test so they can witness it if they choose. If the AI does not attend, the manufacturer proceeds without them, but the qualification is still valid — the AI’s presence is an opportunity, not a requirement. Some Owner specifications are more stringent, requiring mandatory AI witnessing of qualification tests, but this is a contractual requirement beyond the ASME base code requirement.

The Qualification Process — Step by Step

1. Define the intended production weld scope

   Before welding a single coupon, define precisely what production welds the PQR will need to support: the base material P-Number and Group, the welding process, the thickness range, the position, the filler metal F-Number, whether PWHT will be required, and whether notch toughness is required. This scope definition determines what type of coupon to weld and what tests to run — do it upfront or risk running unnecessary tests or missing required ones.

2. Prepare and review a pre-qualification WPS

   Before welding the coupon, prepare a preliminary WPS that specifies the parameters you intend to use for the qualification weld. This is sometimes called the “test WPS” or “pre-qualification WPS.” It records the intended values for every variable — not production ranges, but specific target values for the qualification weld. The pre-qualification WPS is not certified but is used to ensure the coupon is welded in a controlled, documented manner.
3. Notify the Authorised Inspector

   Notify the AI of the planned qualification test date and location with adequate advance notice. The AI may or may not attend — that is their decision — but their opportunity to witness must be documented. Proceed with the test regardless of AI attendance, unless the project contract specifically requires AI witnessing.

4. Weld the test coupon — recording actual parameters

   Weld the test coupon under controlled shop conditions. During welding, measure and record actual parameter values — not the nominal values from the pre-qualification WPS, but the actual measured values for each pass: amperage from a calibrated ammeter, arc voltage from a voltmeter at the electrode, travel speed measured with a stopwatch and measured distance, interpass temperature measured with a calibrated contact thermometer. These actual values are what go on the PQR — they are the record of what was done. Never copy nominal values from the WPS onto the PQR fields that require actual measured values.

5. Submit coupon for mechanical testing

   After welding (and after PWHT if PWHT is required by the test), submit the coupon to an approved mechanical testing laboratory. Specify the test types required per ASME Section IX for the applicable weld type: tensile, bend (face/root/side), and Charpy impact if notch toughness is required. Ensure the laboratory provides certified test reports stating actual test results, specimen dimensions, and a pass/fail conclusion against the applicable code requirements.
6. Complete the PQR form and certify

   Fill out the PQR form (QW-483 for groove welds, QW-484 for fillet welds, QW-485 for stud welds) with all required information. Transfer the actual welding parameters from the weld data records, transfer the test results from the laboratory reports, and complete all identification, base material, filler metal, and technique fields. Have the completed PQR reviewed by a qualified welding engineer or Level III, then obtain the authorised manufacturer certification signature and date.

7. Write the supporting WPS using the qualified PQR

   With the certified PQR in hand, write the production WPS by applying the Section IX essential variable rules to determine the qualified ranges for each parameter. Reference the PQR number(s) on the WPS. Certify the WPS. The document package — PQR + WPS — is now complete and ready for Authorised Inspector review and project submission.

Test Coupon Requirements QW-200.4, QW-461

The test coupon is the physical demonstration that the welding procedure works. Its dimensions, joint geometry, position, and material must be correct — an incorrectly configured coupon will produce a PQR that does not cover the intended production welds, requiring the test to be repeated.

How to Fill the PQR — Section by Section

The ASME QW-483 PQR form is the standard format for groove weld procedure qualification records. The following walkthrough covers every section of the form with the correct entry for each field, the common error for each, and a note on why it matters. The interactive form mock-up below shows how a correctly completed PQR header section appears.

Section 1 — Record Identification and Header

Section 2 — Base Materials

The P-Number System — Why It Is Critical

The P-Number (and Group Number for impact-tested materials) is the single most important base material identifier on the PQR because it determines the range of production materials the PQR qualifies. A PQR on P-No. 1 Group 1 (carbon steel) qualifies welding on all P-No. 1 Group 1 materials, regardless of whether the specific production material specification differs from the coupon specification. A change in P-Number is an essential variable requiring a new PQR.

For a complete guide to P-Numbers, Group Numbers, and F-Numbers including all common material assignments, see our detailed P-Number, F-Number, and A-Number reference guide.

Section 3 — Filler Metals

F-Number and A-Number — Why Both Are Recorded

The F-Number and A-Number serve different purposes in the PQR qualification framework. The F-Number (filler metal group per QW-432) governs the usability characteristics of the electrode — whether it has comparable welding characteristics (e.g. all low-hydrogen SMAW electrodes are F-No. 4; all cellulosic SMAW are F-No. 3). A change in F-Number is an essential variable because it changes the welding behaviour and, for some process-position combinations, the achievable weld quality.

The A-Number (weld metal composition group per QW-442) governs the chemical composition of the deposited weld metal — A-No. 1 is carbon steel weld metal, A-No. 8 is austenitic stainless weld metal. A change in A-Number is an essential variable because it changes the metallurgical composition and properties of the weld metal itself, directly affecting the mechanical test results the PQR is demonstrating.

Section 4 — Welding Conditions (Actual Parameters)

Section 5 — Technique

Mechanical Test Results — Overview

The mechanical test section of the PQR is where the qualification is actually demonstrated — where the coupon proves it meets the required mechanical properties. This section records the actual test results from the laboratory, and the acceptance criteria against which each result is evaluated. A PQR with passing mechanical test results is a qualified procedure; one with failing results is a failed qualification that must be repeated.

Tensile Tests QW-150, QW-153

Two transverse tensile specimens are required for groove weld PQR qualification. Each specimen is machined from the coupon, with the weld axis perpendicular to the load direction, and pulled to failure in a calibrated testing machine.

Tensile Test Acceptance Criteria QW-153

The tensile specimen must not break in the weld at a stress below the specified minimum tensile strength of the base metal (or the lower of the two base metals for dissimilar joints). If failure occurs in the base metal or HAZ at a stress below the specified minimum tensile strength of the base metal, the test is acceptable only if the failure occurred at a stress of not less than 95% of the specified minimum tensile strength of the base metal. Failure in the weld metal at a stress below the base metal minimum is a failure — the procedure qualification has not been demonstrated and must be repeated.

Bend Tests QW-160, QW-163

Bend tests are the primary ductility verification in PQR qualification. For material less than 19 mm thick, two face bend and two root bend specimens are required. For material 19 mm thick or greater, four side bend specimens are used instead — side bends more accurately represent the through-thickness ductility of thick-section welds and detect laminar defects that face or root bends might miss.

Charpy Impact Tests (Notch Toughness) QW-170, QW-171, QW-172

Charpy V-notch impact tests are required as supplementary essential variables when the production WPS is being written for an application that requires demonstrated notch toughness — notably low-temperature service, thick-section pressure vessels under ASME Section VIII UG-84, and nuclear applications. When impact tests are required, they become supplementary essential variables, meaning changes to the welding conditions that affect toughness (heat input increase, preheat decrease, PWHT change) require re-qualification of the impact test.

Hardness Tests QW-200, Owner/NACE requirements

Hardness testing is not mandated by ASME Section IX as a standard PQR test requirement for all applications, but it is required by NACE MR0175/ISO 15156 for sour service applications (to demonstrate HAZ hardness does not exceed HRC 22), by ASME Section VIII for some P-No. 5B (P91) applications, and by most Owner company specifications for critical service. Where hardness testing is required, the results must be recorded on the PQR and the specimen location (weld metal centre, HAZ, and base metal at standardised positions per the applicable hardness traverse pattern) documented clearly.

Essential Variables — How They Link PQR to WPS Range Limits

Essential variables are the welding conditions and parameters whose change from the qualified range requires a new PQR. They are the mechanism by which ASME Section IX ensures that the WPS always falls within the demonstrated capabilities of its supporting PQR(s). Understanding which variables are essential — and which are not — is fundamental to correctly writing WPS range limits from a PQR.

From PQR to Supporting WPS — Deriving the Qualified Ranges

Once the PQR is certified, the WPS is written by applying the Section IX rules to the actual PQR values to determine the allowable ranges for production welding. This is how each key parameter translates:

Common Errors in PQR Documentation — and Their Consequences

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