Is RT or UT required for all ASME IX PQR test welds?

No. QW-195 makes volumetric examination mandatory only when impact testing (QW-171) is included in the qualification, or when the applicable construction code requires it. Standard groove-weld PQRs without impact testing require only visual examination before sectioning.

What acceptance criteria apply to RT of a PQR test coupon under ASME IX?

QW-195 references QW-191 for RT/UT acceptance — the same discontinuity limits as production welds: no cracks, no incomplete fusion, no incomplete penetration. A coupon failing RT is re-welded and re-examined rather than sent to destructive testing.

Can PT or MT substitute for RT when volumetric NDE is required by QW-195?

No. PT and MT are surface methods and cannot satisfy the volumetric examination requirement in QW-195. They may be used as supplementary checks but cannot replace RT or UT when volumetric NDE is required.

Who must witness the NDE of a PQR test coupon?

ASME Section IX itself does not name a required witness for coupon NDE. The applicable construction code (B31.3, BPVC Section I, etc.) and the Authorized Inspector (AI) requirements govern. Most shops have the AI or a certified NDE examiner review RT films before the coupon is sectioned.

ASME IX QW-195: NDE of PQR qualification test welds

ASME Section IX QW-195 governs NDE of PQR test welds before mechanical testing. Here's what examination methods apply, when they're required, and how to pass.

When you are qualifying a welding procedure under ASME Section IX, the test coupon has to demonstrate that the process produces sound weld metal — not just that the welder can lay a bead. Before the coupon goes to the lab for tensile bars and bend specimens, QW-195 establishes whether NDE applies and what it requires. Getting this right keeps your qualification package defensible when an Authorized Inspector or third-party auditor looks it over.

What QW-195 actually covers

QW-195 is a short article in ASME Section IX that establishes examination requirements for test coupons produced during procedure qualification. It references three other QW articles:

QW-191 — the acceptance criteria for radiographic and ultrasonic examination of test welds
QW-142 — the examination requirements specific to fillet weld test coupons
QW-171 — the impact testing article, which is the primary trigger for volumetric examination under QW-195

The core rule: volumetric examination (RT or UT) of the groove-weld test coupon is required when the qualification includes Charpy V-Notch (CVN) impact testing. For standard qualifications without impact testing, visual examination of the coupon before sectioning is typically sufficient to satisfy QW-195.

Why impact testing triggers volumetric examination

Impact test specimens must be taken from defined locations in the weld cross-section per QW-171.1. If the coupon contains a buried porosity cluster, a lack-of-fusion void, or an incomplete-penetration discontinuity in the impact specimen zone, the test result will reflect the flaw rather than the inherent material toughness. The procedure would then be qualified on degraded data.

Volumetric examination before sectioning confirms the weld is sound throughout, ensuring that impact results represent the process at its actual performance level, not a region contaminated by a defect. This is the same logic that drives RT acceptance of pressure-vessel shell courses before hydrostatic testing — confirm the baseline is clean before relying on the test result.

Visual examination: the baseline requirement

Whether or not volumetric NDE is required, ASME Section IX expects visual examination of the test coupon before destructive testing. The inspector looks for:

Cracks in the weld and the heat-affected zone
Incomplete fusion at weld toes and at the root
Underfill or concavity that exceeds acceptable limits
Surface irregularities indicating a fundamental process problem

A coupon that fails visual examination signals something went wrong during the qualification weld: wrong preheat, wrong technique, contaminated base metal, or a parameter that drifted outside the intended range. The responsible path is to document the failure, investigate, and re-weld a new coupon — not proceed to destructive testing on a visually defective sample that will produce unrepresentative results.

For an overview of how NDE fits into structural production weld acceptance, see NDE method selection for structural welds.

RT acceptance under QW-191

When radiographic examination is performed on a PQR test coupon, QW-191.1 specifies the acceptance criteria. Unacceptable conditions include:

Cracks — any length, any orientation
Incomplete fusion or penetration — any evidence of lack of bond to the base metal or at the root
Elongated slag inclusions — length exceeding limits in QW-191.1.1 (governed by ratio of length to thickness)
Porosity clusters — area fraction exceeding the limits in QW-191.1.2

These are conceptually equivalent to RT acceptance criteria from AWS D1.1 structural or API 1104 pipeline work, though the ASME formatting differs. The underlying philosophy is consistent: the weld must show no planar or extensive volumetric discontinuities before its mechanical properties are used to support a qualified procedure.

If the coupon fails RT, the qualification is not valid. The coupon is rejected, root cause is investigated, and a new coupon is welded and examined before destructive testing proceeds.

UT as an alternative to RT

QW-191.2 allows UT as an alternative to RT for volumetric examination of test coupons. The UT must meet the acceptance requirements of the applicable construction code's UT procedures.

In practice, RT is more common for coupon examination because it provides a permanent film record that the AI and owner can independently review. UT reports are acceptable but require an examiner trained in the specific technique, calibrated to applicable reference blocks. For a one-off PQR coupon, the marginal cost of RT film is often lower than configuring UT calibration for a single piece.

Where digital RT (computed radiography or digital detector arrays) is available, the digital image file serves as the permanent record in place of film. The acceptance criteria under QW-191 apply equally to film and digital RT.

Fillet weld test coupons: QW-142

Fillet weld procedure qualifications are examined under QW-142, which specifies macroetch inspection rather than volumetric NDE. The coupon is sectioned transversely at specified intervals, etched with a suitable reagent (typically a nital or ferric chloride solution), and examined for:

Weld profile — leg lengths, throat, convexity or concavity
Fusion to the base metal across both legs
Root penetration, if specified by the applicable code
Absence of cracks and significant porosity in the cross-section

One acceptable macroetch section from the mid-length of the fillet coupon satisfies the examination requirement under QW-142. Volumetric NDE is not required for fillet weld procedure qualification regardless of whether impact testing is included.

See how a PQR tensile and bend test report is read and reviewed for the mechanical testing side of qualification documentation.

The sequence when impact testing is included

When CVN impact testing is part of the qualification, the correct examination sequence is:

Weld the test coupon per the proposed WPS parameters (within the essential variable ranges being qualified).
Allow the coupon to reach ambient temperature.
Perform visual examination — reject and re-weld if unacceptable.
Perform RT or UT per QW-191 — reject and re-weld if unacceptable.
Section the coupon; remove impact specimens from the designated locations per QW-171.1.
Perform impact testing at the specified test temperature; record absorbed energy.
Complete tensile and guided bend tests on remaining specimens.
Compile the PQR package.

Steps 3 and 4 gate access to steps 5 through 7. A shop that skips the NDE step and goes directly to sectioning has produced an incomplete qualification regardless of how good the mechanical test results look. The coupon's soundness before sectioning is a required datum, not a formality.

The Authorized Inspector's role

ASME Section IX is a qualification standard, not a construction code, and it does not specify who must observe the coupon NDE. The applicable construction code invokes Section IX and specifies AI involvement:

BPVC Section I (power boilers) and Section VIII (pressure vessels) require the AI to countersign the completed PQR.
B31.3 (process piping) requires the owner or owner's engineer to certify the qualification records, with AI involvement when specified.

In practice, the AI typically reviews RT films or UT reports as part of the PQR package review before countersigning. An AI who signs a PQR package that lacks required NDE documentation is putting their certification at risk. Most experienced AIs ask for the NDE records before the mechanical test results, not after.

Building the complete PQR package

A complete ASME IX PQR package for a groove weld qualification with CVN impact testing includes:

Completed PQR form (QW-483 format) with all essential and supplementary essential variables documented
WPS used during the qualification weld — shows parameter ranges intended for qualification
Welder/operator WPQ for the individual who made the test weld
Visual examination record — inspector, date, findings
RT film envelope and interpretation report, or UT examination report — showing coupon identification, film/record identification, and acceptance
Mechanical test results — tensile, guided bend, CVN impact (temperature, absorbed energy, specimen dimensions)
AI countersignature per the applicable construction code

For broader ASME IX qualification management, see ASME IX QW-451 thickness and position qualification ranges and ASME IX welder qualification and the QW-322 period of performance.

Managing multiple PQRs, tracking which essential variable ranges they cover, and keeping the NDE and mechanical test records organized across a shop's procedure library is where purpose-built qualification management tools earn their cost. See our qualification and audit management capabilities for what a connected system covers.

Rule library based on AWS D1.1:2025; verify against your governing edition. ASME Section IX citations reflect the 2021 edition — confirm with your applicable edition.