What tests are required to qualify a welder under ASME IX QW-300?

ASME IX QW-300 requires at least one of three test methods: radiographic examination (RT), destructive bend testing (face, root, or side bends per QW-160), or fracture/nick-break testing where permitted. The test coupon must satisfy the applicable position and thickness ranges per QW-452, and the welder must pass with acceptable results under the chosen method. For most groove weld qualifications, RT or side bends are the primary options; fillet weld qualifications typically use macro examination.

Can RT always replace destructive bend testing for ASME IX welder qualification?

No. RT is allowed as an alternative to destructive testing for groove welds under QW-302.2, but only when the production process permits RT of the test coupon. When RT is used, the radiograph must meet acceptance criteria in QW-191 (for groove welds) or the applicable NDE standard. RT cannot substitute for fillet weld qualification testing — fillet welds require macro examination or fracture testing per QW-180. Some organizations' authorized inspection agencies also require destructive testing as a policy regardless of code allowance.

What is the difference between welder performance qualification and welding procedure qualification under ASME IX?

Procedure qualification (QW-200 series) demonstrates that a welding process with specific variables can produce welds meeting mechanical properties — it qualifies the procedure, not the person. Performance qualification (QW-300 series) demonstrates that an individual welder can deposit sound weld metal following a qualified WPS — it qualifies the welder. A qualified WPS is a prerequisite for welder performance qualification; the welder takes the test using the WPS being qualified to their personal record.

How long does ASME IX welder performance qualification stay valid?

Under QW-322, a welder's performance qualification remains valid as long as the welder uses the process during a 6-month period. A 6-month gap without using the qualified process requires requalification — the record lapses. Additionally, welder records lapse if there is specific reason to question the welder's ability (e.g., failure to follow WPS, poor quality trend). The company must track welder continuity through weld records, traveler sign-offs, or another documented system.

Jul 23, 20267 min read

ASME IX QW-300: Welder Performance Qualification Tests

QW-300 governs how welders are tested under ASME IX: which test methods apply, when RT substitutes for destructive testing, and what acceptance criteria must be met.

ASME IX WPQ welder qualification QW-300 QW-302 pressure vessel

ASME Section IX Article III — the QW-300 series — defines how welder performance qualification works: what the test coupon must look like, which examination methods are acceptable, what the acceptance criteria are, and how qualification ranges are determined. It is a distinct body of requirements from the procedure qualification rules in Article II (QW-200 series), and mixing them up is a recurring mistake in shops that weld to both ASME IX and AWS D1.1.

This article covers the QW-300 series systematically: test types, examination options, fillet versus groove, acceptance criteria, and the continuity requirement that governs record expiration.

QW-300 scope: performance, not procedure

Article III applies specifically to welders (manual process) and welding operators (machine/automatic process). QW-300.1 states that the purpose of welder performance qualification is to determine the ability of a welder to deposit sound weld metal following a qualified welding procedure specification. This framing matters because:

The welder must use a qualified WPS during the performance test. An organization cannot run performance qualification tests against an unqualified procedure.
The test evaluates the welder's skill, not the procedure's adequacy. A well-executed coupon with acceptable NDE results qualifies the welder even if the test coupon itself is relatively thin or simple.
Performance qualification is employer-specific under ASME IX. A qualification issued by one employer is not automatically transferable to another unless the new employer verifies the prior record and the process, position, and variable ranges apply to the new work.

Test coupon geometry and position

The test coupon thickness and joint configuration determine the qualification ranges per QW-452. Key points:

Groove welds: A test coupon of base metal thickness t qualifies the welder for production welds in the range 1t to 2t (up to 3/4 in [19 mm] on the high end when the coupon is 3/4 in or greater). The position of the test coupon (1G flat, 2G horizontal, 5G multiple fixed, 6G inclined) qualifies the welder for specific production positions per QW-461.9. A 6G (45° inclined pipe) coupon qualifies all positions.

Fillet welds: Separate qualification rules apply. A welder who qualifies on a groove weld test is automatically qualified to make fillet welds in the positions qualified by the groove test, per QW-303.1. A welder who qualifies only on a fillet weld test is qualified only for fillet welds.

Pipe diameter: For pipe groove weld qualification, QW-452.3 limits the qualified pipe outside diameter range based on the test coupon OD — smaller diameter tests qualify less range than larger diameters.

QW-302 examination options

QW-302 establishes the acceptable test methods. The choice of method is the employer's (or authorized inspection agency's) and must be documented on the welder performance qualification record (WPQR / Form QW-484).

RT in lieu of destructive testing (QW-302.2)

Radiographic examination is permitted as an alternative to bend testing for groove weld performance qualification when:

The production work involves a process and joint geometry where RT is practical (typically butt welds in pipe or plate)
The RT is performed by a qualified NDE technician and the film or digital image is evaluated per QW-191 acceptance criteria (AWS D1.1 uses different acceptance criteria — do not cross-apply)
The coupon length meets ASME RT coverage requirements for the test length to be evaluated

RT qualification is particularly common for pipe welder qualification in shops that make many pipe butt welds, because RT testing is faster and avoids destroying the coupon. The tradeoff: RT does not detect all planar flaws as reliably as side bends, and some owner specifications or AI-agency quality programs require destructive testing regardless.

Bend testing (QW-160 series)

Bend testing is the default destructive method for groove weld qualification:

Face bend (QW-161.1): The face of the weld becomes the tension surface. Required when the base metal is 3/8 in [10 mm] or less.
Root bend (QW-161.2): The root of the weld becomes the tension surface. Also required for thin material.
Side bend (QW-161.3): A through-thickness cross-section of the weld is bent. Used for material over 3/8 in [10 mm]. Two side bends are required per test coupon for groove welds.

Bend specimens must be bent through an angle of at least 180° over a mandrel with dimensions per QW-163. Acceptance: after bending, no open discontinuity exceeding 1/8 in [3 mm] in any direction shall be present on the convex surface, except at the specimen edges.

See guided bend test PQR requirements AWS D1.1 for the similar (but not identical) AWS D1.1 PQR test — note that procedure qualification bends and performance qualification bends use the same physical test but different acceptance criteria and specimen counts.

Fracture test for fillet welds (QW-182)

Fillet weld performance qualification uses the fillet weld break test (fracture test). The weld is fractured along its length and the fracture surface examined for:

Lack of fusion
Cracks
Porosity in excess of the limits in QW-182

Macro examination is an alternative for fillet weld performance qualification, particularly useful for small weld sizes where fracture testing is not practical.

QW-191 acceptance criteria for RT-qualified welds

When RT is used in place of bend testing, the radiographic image must meet acceptance criteria in QW-191. These are generally aligned with ASME Section V Article 2 examination requirements, and the acceptance criteria for welder performance qualification are:

No cracks or lack of fusion
No incomplete penetration in the weld root
Porosity not exceeding the limits in QW-191.2 (based on a comparison radiograph)
No slag inclusions longer than 1/4 in [6 mm] or combined slag in any 6 in [150 mm] of weld exceeding 3/4 in [19 mm]

These limits are stricter in some respects than ASME B31.3 production weld RT acceptance criteria. A welder qualification RT image that would fail QW-191 might still be acceptable under some production standards — but a performance test that does not meet QW-191 is a failed test, regardless of production inspection outcome.

The WPQR record: QW-484

Every welder performance qualification test must be documented on a Welder/Welding Operator Performance Qualification Record, Form QW-484 (or an equivalent document containing the same information). The record must include:

Welder name and identification stamp (if used)
WPS used during the test
Base metal specification and thickness
Filler metal specification, classification, and diameter
Test position
Examination results (RT film/image number or bend/fracture results)
Date of test
Witnessing authorized inspector signature (where required)

The QW-484 is the employer's property and must be retained as long as the welder is active and for a defined period after. Unlike AWS D1.1 WPQ records, ASME IX does not specify a mandatory retention period beyond the period the qualification is valid — but best practice and quality system requirements typically specify 3–10 years after last use.

QW-322: continuity and lapse

Performance qualification lapses under two conditions:

6-month gap in process use. If a welder does not use a specific welding process (SMAW, GTAW, GMAW, etc.) during any 6-month period, the performance qualification for that process lapses and the welder must requalify. The 6-month interval applies per process — a GTAW qualification does not lapse just because the welder has been doing SMAW full time for 8 months.
Specific reason to question ability. Per QW-322.2, an employer may find specific reason to question the welder's ability at any time — typically triggered by repeated weld rejections, NDE failures, or non-conformance findings. This is a quality-system driven lapse, not a time-based one.

Tracking continuity requires a documented record of production weld activity by process. Shops that weld to ASME IX need a system — whether manual logs, shop travelers, or a welder continuity tracking platform — that can demonstrate the 6-month continuity on demand. See ASME IX welder qualification QW-322 period for more on continuity management.

For shops managing both AWS D1.1 and ASME IX welder qualifications simultaneously, the 6-month rule is identical in principle but operationally separate — each code governs its own records. See welder performance qualification WPQ AWS D1.1 for the D1.1 side.

Scope of qualification from a single test

One of the most useful aspects of QW-300 is the qualification range table in QW-452. A single test coupon can qualify a broad range of production work:

A 6G fixed pipe test at 1 in wall thickness qualifies all positions and qualifies production thicknesses from 3/16 in through unlimited on pipe, provided no additional essential variables are changed
A flat plate test at 1 in qualifies 1G/2G/3G positions (if 3G was tested) and production thicknesses up to 2 in

Understanding the qualification range from a single test is important for shops that need to qualify welders for multiple product lines without running separate tests for each combination. When in doubt, run a more demanding test (6G pipe, larger thickness) rather than the minimum — the broader qualification range often avoids a second test later.

For shops that track qualification matrices and want to manage WPS-to-welder assignment without manual spreadsheets, wpswelding.com/pricing covers the tooling that links qualified WPS records to welder PQ ranges.

Summary

ASME IX QW-300 performance qualification is a welder test, not a procedure test. The test methods — RT in lieu of bends, or destructive bend/fracture testing — must match the examination requirements in QW-302 and QW-191. Documentation on QW-484 must be complete and retained. The 6-month continuity rule in QW-322 requires active tracking — a welder whose record has lapsed is an unqualified welder, regardless of experience, until the retest is passed. When the code offers broad qualification ranges from a single demanding test, use them.

FAQ

Frequently asked.

What tests are required to qualify a welder under ASME IX QW-300?: ASME IX QW-300 requires at least one of three test methods: radiographic examination (RT), destructive bend testing (face, root, or side bends per QW-160), or fracture/nick-break testing where permitted. The test coupon must satisfy the applicable position and thickness ranges per QW-452, and the welder must pass with acceptable results under the chosen method. For most groove weld qualifications, RT or side bends are the primary options; fillet weld qualifications typically use macro examination.
Can RT always replace destructive bend testing for ASME IX welder qualification?: No. RT is allowed as an alternative to destructive testing for groove welds under QW-302.2, but only when the production process permits RT of the test coupon. When RT is used, the radiograph must meet acceptance criteria in QW-191 (for groove welds) or the applicable NDE standard. RT cannot substitute for fillet weld qualification testing — fillet welds require macro examination or fracture testing per QW-180. Some organizations' authorized inspection agencies also require destructive testing as a policy regardless of code allowance.
What is the difference between welder performance qualification and welding procedure qualification under ASME IX?: Procedure qualification (QW-200 series) demonstrates that a welding process with specific variables can produce welds meeting mechanical properties — it qualifies the procedure, not the person. Performance qualification (QW-300 series) demonstrates that an individual welder can deposit sound weld metal following a qualified WPS — it qualifies the welder. A qualified WPS is a prerequisite for welder performance qualification; the welder takes the test using the WPS being qualified to their personal record.
How long does ASME IX welder performance qualification stay valid?: Under QW-322, a welder's performance qualification remains valid as long as the welder uses the process during a 6-month period. A 6-month gap without using the qualified process requires requalification — the record lapses. Additionally, welder records lapse if there is specific reason to question the welder's ability (e.g., failure to follow WPS, poor quality trend). The company must track welder continuity through weld records, traveler sign-offs, or another documented system.