9.3 ASME Standard Documentation: Auditing WPS, PQR, and WPQ Forms

9.3 ASME Standard Documentation: Auditing WPS, PQR, and WPQ Forms

Core Principle: In ASME Section IX quality assurance, welding documentation forms an interdependent legal triad: the Procedure Qualification Record (PQR) is the factual historical record of what was welded and mechanically tested; the Welding Procedure Specification (WPS) is the operational recipe directing shop and field production; and the Welder Performance Qualification (WPQ) verifies an individual's manual skill. An auditor must verify that every operational instruction on the WPS is fully supported by the certified data on the PQR.

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1. Overview and Legal Status of ASME Standard Forms (Appendix B)

In Nonmandatory Appendix B, ASME Section IX provides sample forms designed to assist fabricators in documenting their welding procedures and personnel qualifications:

• Form QW-482: Suggested Format for Welding Procedure Specifications (WPS)
• Form QW-483: Suggested Format for Procedure Qualification Records (PQR)
• Form QW-484A / QW-484B: Suggested Format for Welder / Welding Operator Performance Qualifications (WPQ / WOPQ)

The "Nonmandatory" Legal Distinction

Candidates frequently misunderstand why these forms reside in a "Nonmandatory" appendix. Section IX mandates the content, not the visual format. A manufacturer or engineering contractor is legally permitted to design proprietary forms, utilize specialized corporate database formats, or implement computerized welding management software. However, the resulting documentation must record every essential, supplementary essential (when applicable), and nonessential variable mandated by Article II (QW-250 series) for the WPS and PQR, and Article III (QW-350 series) for the WPQ.

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2. Anatomy and Legal Roles of the Documentation Triad

+-----------------------------------------------------------------------------------------+
|                        THE WORKFLOW RELATIONSHIP IN SECTION IX                          |
+-----------------------------------------------------------------------------------------+
|  1. WELD TEST COUPON    --> Record actual parameters on test coupon                     |
|  2. MECHANICAL TESTING  --> Perform tensiles, bends, impacts in testing lab             |
|  3. CERTIFY PQR         --> Manufacturer signs & dates Form QW-483                      |
|  4. DRAFT WPS           --> Formulate production ranges on Form QW-482 based on PQR    |
|  5. QUALIFY WELDER      --> Test welder on coupon; document results on Form QW-484      |
|  6. PRODUCTION WELDING  --> Welder follows WPS on shop floor or field installation      |
+-----------------------------------------------------------------------------------------+

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3. Step-by-Step Line-by-Line WPS Audit Against Supporting PQR(s)

When a Certified Welding Inspector (CWI) or Authorized Inspector (AI) reviews a WPS submitted for production welding, they must execute a rigorous cross-examination against the supporting PQR(s). Every variable must align with Section IX rules.

Variable-by-Variable Audit Protocol

1. Joints (QW-402):

   • Check backing requirements: If the PQR coupon was welded without backing, the WPS may permit welding with or without backing (for standard processes). If the PQR was welded with backing, the WPS cannot authorize open-root welding without backing if backing deletion is an essential variable.

2. Base Metals (QW-403):

   • P-Number Verification: Verify that the base metal P-Number listed on the WPS matches the P-Number combination qualified on the PQR per Table QW-424.1.
   • Group Number & Toughness: If the WPS is intended for impact-tested service, verify that the PQR recorded Charpy impact specimens and that the base metal Group Numbers match the PQR coupon per QW-403.5.
   • Base Metal Thickness Range ($T$): Check the coupon thickness $T$ recorded on the PQR. Cross-reference Table QW-451.1 to confirm that the minimum and maximum base metal thickness range on the WPS does not exceed code limits (e.g., a $1/2\text{ in.}$ coupon qualifies $3/16\text{ in.}$ to $1.0\text{ in.}$; a WPS listing $2.0\text{ in.}$ max is noncompliant!).

3. Filler Metals (QW-404):

   • F-Number: The F-Number on the WPS must be identical to the F-Number on the PQR per QW-404.4.
   • A-Number: For ferrous metals, the A-Number on the WPS must match the PQR weld deposit analysis or CMTR per QW-404.5.
   • Deposited Thickness ($t$): The maximum deposited weld metal thickness per process on the WPS cannot exceed $2t$ from the PQR (or $8.0\text{ in.}$ if Note 1 applies for $t \ge 3/4\text{ in.}$ with $\ge 3$ layers).

4. Positions (QW-405):

   • Under standard procedure qualification, a coupon welded in any position (e.g., 1G flat) qualifies all positions (flat, horizontal, vertical, overhead) for production, unless impact testing is mandated. When impact testing applies, QW-405.2 makes a change from vertical-up to vertical-down an essential variable!

5. Preheat and Interpass Temperature (QW-406):

   • The 100°F Decrease Rule (QW-406.1): The minimum preheat temperature specified on the WPS cannot be more than $100\text{°F}$ ($55\text{°C}$) lower than the preheat temperature recorded on the PQR. (Example: If the PQR recorded $250\text{°F}$ preheat, the WPS cannot specify lower than $150\text{°F}$). Specifying $70\text{°F}$ (ambient) on the WPS would be a fatal code violation!
   • Maximum Interpass (QW-406.3): If impact testing applies, an increase in maximum interpass temperature above that recorded on the PQR is a supplementary essential variable.

6. Postweld Heat Treatment (PWHT) (QW-407):

   • Paragraph QW-407.1 mandates that changing the PWHT condition is an essential variable. If the PQR was tested with no PWHT, the WPS cannot authorize PWHT; if the PQR was PWHT'd, the WPS must specify PWHT within the qualified temperature and holding time ranges.

7. Electrical Characteristics and Heat Input (QW-409):

   • Verify current type (AC/DC) and polarity (DCEP/DCEN).
   • Heat Input Calculation (QW-409.1): When impact testing applies, the WPS must establish maximum heat input limits based on the PQR parameters: $\text{Heat Input } (J/\text{in}) = \frac{\text{Voltage } (V) \times \text{Amperage } (A) \times 60}{\text{Travel Speed } (\text{in/min})}$ An increase in heat input over the PQR maximum is a supplementary essential variable.

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4. Auditing PQR Mechanical Test Results (Tensile & Bend Tests)

A critical duty of the welding inspector is auditing the laboratory mechanical test data recorded on page 2 of Form QW-483. Mathematical calculation errors and misapplied code thresholds will invalidate the qualification.

Tensile Test Calculation and Verification Protocol (QW-150)

Under Table QW-451.1, two tensile specimens are required for procedure qualification. The inspector must verify the mathematics:

1. Cross-Sectional Area ($A$): Multiply specimen width ($W$) by thickness ($T$): $A = W \times T \quad (\text{sq in. or mm}^2)$
2. Ultimate Tensile Strength ($\sigma$): Divide maximum applied load ($P$) by cross-sectional area ($A$): $\sigma = \frac{P}{A} \quad (\text{psi, ksi, or MPa})$
3. Comparison Against Table QW/QB-422: Find the base metal specification in Table QW/QB-422 and identify the minimum specified tensile strength ($S_u$).

+-----------------------------------------------------------------------------------------+
|                   TENSILE TEST ACCEPTANCE RULES (PARAGRAPH QW-153.1)                    |
+-----------------------------------------------------------------------------------------+
| RULE 1: BREAK IN WELD METAL                                                             |
|  - Tensile strength MUST be >= minimum specified tensile strength of the base metal!    |
|  - If base metal Su = 70.0 ksi, weld metal break must be >= 70.0 ksi.                   |
|-----------------------------------------------------------------------------------------|
| RULE 2: BREAK IN BASE METAL OUTSIDE WELD (THE 5% RULE - QW-153.1(d))                    |
|  - If specimen breaks in the base metal outside the weld or fusion line, the test is    |
|    ACCEPTABLE if the strength is NOT more than 5% below the specified minimum tensile    |
|    strength of the base metal!                                                          |
|  - Acceptance Threshold = 0.95 * Su                                                     |
|  - Example: For SA-516 Gr. 70 (Su = 70.0 ksi), min acceptable = 0.95 * 70.0 = 66.5 ksi! |
+-----------------------------------------------------------------------------------------+

Worked Exam Scenario: The 5% Base Metal Break Rule

• PQR Data: Coupon welded from ASTM A516 Grade 70 plate ($S_u = 70.0\text{ ksi}$).
• Specimen T-1: Width = $0.750\text{ in.}$, Thickness = $0.500\text{ in.}$ $A = 0.750 \times 0.500 = 0.375\text{ sq in.}$ $\text{Max Load } P = 25,200\text{ lb}$ $\text{Tensile Strength } \sigma = \frac{25,200}{0.375} = 67,200\text{ psi} = 67.2\text{ ksi}$ Failure Location: Base metal, $1.5\text{ inches}$ outside the fusion boundary.
• Auditor Evaluation: Does Specimen T-1 pass?
  • Specified minimum tensile strength $S_u = 70.0\text{ ksi}$.
  • Under QW-153.1(d), because the break occurred in the base metal, the specimen can fail up to 5% below $S_u$: $\text{Threshold} = 0.95 \times 70.0\text{ ksi} = 66.5\text{ ksi}$
  • Since $67.2\text{ ksi} \ge 66.5\text{ ksi}$, Specimen T-1 PASSES!

Guided-Bend Test Verification Protocol (QW-160 & QW-163)

Table QW-451.1 specifies transverse bend specimens (4 side bends for $T \ge 3/8\text{ in.}$; or 2 face and 2 root bends for $T < 3/8\text{ in.}$). The inspector must audit the post-bend visual examination against paragraph QW-163:

• General Discontinuity Limit: The guided-bend specimens must have no open discontinuity exceeding $1/8\text{ inch}$ ($3\text{ mm}$) measured in any direction on the convex surface of the specimen after bending.
• Corner Cracks Exception: Cracks occurring at the corners of the specimen during bending are not considered, unless there is definite evidence that they result from lack of fusion, slag inclusions, or other internal discontinuities. If caused by internal defects, corner cracks are limited to a maximum of $1/4\text{ inch}$ ($6\text{ mm}$).

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5. Certification Signatures and Legal Enforceability

Perhaps the single most overlooked yet fatal error on ASME documentation concerns the certification signature block.

The Mandatory PQR Certification Statement

Paragraph QW-200.2(a) and the bottom of Form QW-483 mandate the following explicit legal declaration:

"We certify that the statements in this record are correct and that the test welds were prepared, welded, and tested in accordance with the requirements of Section IX of the ASME Boiler and Pressure Vessel Code."

+-----------------------------------------------------------------------------------------+
|                    THE LEGAL STATUS OF CERTIFICATION BLOCKS                             |
+-----------------------------------------------------------------------------------------+
| PQR CERTIFICATION BLOCK: MANDATORY UNDER LAW!                                           |
|  - Must be signed and dated by an authorized representative of the manufacturer         |
|    or contractor who conducted the qualification.                                       |
|  - An unsigned or undated PQR has ZERO legal status under ASME BPVC.                    |
|  - A WPS supported by an uncertified PQR is void, and all production welds made under   |
|    it are legally noncompliant and subject to rejection!                                |
|-----------------------------------------------------------------------------------------|
| WPS SIGNATURE BLOCK: ORGANIZATIONAL GOVERNANCE                                          |
|  - Section IX does not explicitly mandate a signature on Form QW-482, but requires the  |
|    WPS to reference the supporting certified PQR(s). Company QA programs require sign-off|
|-----------------------------------------------------------------------------------------|
| WPQ CERTIFICATION BLOCK: MANDATORY UNDER QW-301.4                                       |
|  - Must be signed and dated by the manufacturer/contractor certifying that the welder    |
|    welded the coupon in compliance with Section IX.                                     |
+-----------------------------------------------------------------------------------------+

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6. The Auditor's Checklist: Fatal Nonconformances vs. Clerical Errors

An experienced inspector must distinguish between minor clerical omissions (which can be resolved by administrative correction) and fatal code nonconformances (which legally invalidate the procedure and require immediate work stoppage or re-welding).