Repair weld WPS requirements under AWS D1.1:2025

A repair weld is not simply welding the defective area again. AWS D1.1:2025 treats weld repairs as a controlled operation requiring engineer authorization, a WPS that actually covers the repair conditions, documented defect removal, and post-repair NDE. Shops that grab the original construction WPS and start welding without reviewing these requirements create quality-record gaps that surface in audits — and liability exposure if the repair itself fails.

Why repair conditions differ from new construction

The fabrication conditions that produced the original WPS may not apply to a repair:

Restraint is higher. Original weld-joint components are loose during setup — they can move to relieve thermal shrinkage. When a repair is made to an assembled structure or a partially fabricated weldment, the joint is constrained by surrounding material. Residual stress from the original weld adds to the repair's shrinkage stress. Higher restraint means higher risk of hydrogen-induced cracking (HIC), and that means the preheat requirement goes up.

Base metal has been thermally altered. The HAZ of the original weld has already been austenitized, partially transformed, and possibly tempered through multiple thermal cycles. Carbon redistribution in the HAZ can locally elevate carbon equivalent. If air carbon arc gouging (ACAG) is used for defect removal and the surface is not properly dressed, carbon pickup from the graphite electrode adds another source of elevated CE in the repair area.

Joint geometry changes. After removing a defect by grinding or gouging, the cavity may not match any prequalified Annex B geometry. If the original WPS was prequalified (no PQR), a cavity that falls outside prequalified joint limits may require a procedure-qualified WPS for the repair.

Position may differ. A defect in the overhead position of an in-service assembly cannot be repaired using the flat-position WPS from original construction unless that WPS covers overhead.

Engineer authorization: before the grinder comes out

AWS D1.1:2025 requires that the engineer be notified of any repair to a structural weld, and that substantive repairs receive written authorization before work begins. "Substantive" includes any repair that affects the structural integrity calculation — cracks, lamellar tears, incomplete fusion in the load path, undersized throat on CJP joints.

The QC manager's documentation package before repair starts:

• NDE report identifying the defect: type, location, extent, depth
• Repair plan: method of removal, repair WPS number, preheat specification, post-repair NDE plan
• Engineer authorization: email response, formal repair procedure approval, or RFI disposition

Starting a repair without this documentation is a QC deficiency regardless of whether the repair itself turns out sound. See Common WPS deficiencies in third-party audits.

Removing the defect completely

Complete defect removal is required before depositing repair weld metal. Partially removed defects remain as crack initiation sites.

Grinding: Appropriate for surface cracks and undercut. After grinding, perform MT or PT to confirm full removal. Confirm that the remaining base metal cross-section at the repair location is sufficient for the design load path.

Air carbon arc gouging (ACAG): Efficient for volumetric defects — porosity clusters, slag inclusions, incomplete fusion, cracks with depth. After gouging:

1. Dress the cavity surface by grinding at least 1/16 inch [1.6 mm] to remove the carburized layer left by the graphite electrode
2. Inspect the dressed surface by MT or PT before welding

Skipping the grind-after-gouge step leaves a carbon-enriched surface. Welding directly over it increases the local CE of the repair HAZ and can produce a crack in the same location as the original defect.

MT or PT after removal: This is a hold point, not a suggestion. It confirms complete defect removal. An inspector who signs off on a repair without post-removal NDE confirmation has no documentation that the defect was fully removed.

Rule library based on AWS D1.1:2025; verify against your governing edition.

Preheat for repair welds

Repair welds consistently require higher preheat than the equivalent new-construction joint. Contributing factors:

• Higher restraint increases residual stress, which amplifies HIC susceptibility
• Potential carbon pickup from ACAG if the surface was not properly dressed
• Multiple prior thermal cycles may have left a partially tempered martensitic structure in the HAZ that is more sensitive to hydrogen than virgin base metal

As a practical starting point, many QC programs set repair preheat one temperature step above the new-construction minimum in the applicable preheat table for the base metal group and thickness. Document this explicitly in the repair WPS or approved repair procedure — not as a verbal instruction to the welder.

Maintain preheat throughout the repair sequence, not just at first arc. Repair welds are typically shorter and interrupted more often (stops for NDE checks, fit verifications) than original construction runs, which creates more opportunities for the joint to cool below preheat. See Preheat and interpass temperature documentation on a WPS for verification requirements.

When a new PQR is required for a repair

Review the original WPS qualification against the repair conditions using Table 6.6 essential variables:

If any essential variable is out of range, the original WPS does not cover the repair. Either identify a qualified WPS in the procedure library that does cover the repair conditions, or qualify a new one. See When does a PQR require requalification?.

Post-repair NDE

Post-repair NDE must meet the same minimum requirements as the original joint — and for CJP structural welds, that means volumetric inspection:

• Visual inspection of the completed repair weld: profile, crater fill, undercut
• MT or PT on the repair weld and at least 1 inch [25 mm] beyond each weld end
• UT or RT for CJP groove welds in tension load path per the project NDE plan

Accept the completed repair only after all NDE results are within acceptance criteria. If post-repair UT reveals a new indication, the repair did not solve the problem — re-evaluate the root cause before attempting a second repair. Two failed repairs on the same joint require written engineer direction before a third attempt.

See NDE documentation and the audit packet.

The repair record

The repair record is the document trail that closes out a defect finding. It belongs in the project quality file alongside weld maps and original NDE reports. A complete repair record includes:

• Joint/weld ID from the weld map — traceable to the original drawing and weld number
• Pre-repair NDE report: document type, method, acceptance criteria reference, finding location and dimensions
• Defect removal log: method, ACAG parameters if used, grind-after-gouge confirmation, pre-repair-weld NDE (MT/PT after removal)
• Repair WPS number and revision in effect at time of repair
• Welder ID and qualification scope — confirm the welder is qualified for the process and position used in the repair
• Preheat and interpass temperature log during repair
• Post-repair NDE report: method, acceptance criteria, results, inspector sign-off
• Engineer authorization reference: document number or email timestamp

This documentation chain is what a third-party auditor verifies when reviewing a repaired joint. A joint listed on the weld map as "repaired" with no corresponding repair record is a finding that can hold up a project closeout. See Weld map and WPS traceability in production.

For shops building a digital audit packet that includes repair records, weld maps, and NDE reports in one exportable file, see our pricing and plan options.