WPS welding: what a welding procedure specification is.

Three documents, three different jobs. Mixing them up is the most common audit finding in small shops.

A PQR backs up a WPS that is qualified by test. A WPQ qualifies the welder, and under AWS D1.1 that qualification lapses if the welder goes six months without using the process (see welder continuity). More on the PQR in what is a PQR.

The content is set by the code, not the form. AWS D1.1:2025 gives a sample form in Annex J (Form J-1); ASME Section IX uses QW-482 (see QW-482 and QW-483 explained). Either way a WPS covers:

Identification

WPS number, revision, date, the supporting PQR number (if qualified by test), and who prepared and approved it.

Process

SMAW, GMAW, FCAW, SAW or GTAW, and for GMAW the transfer mode. Short-circuit GMAW is not prequalified under AWS D1.1.

Joint design

Joint type, groove or fillet detail, groove angle, root opening, root face, backing and backgouging.

Base metal

Specification and grade, the AWS D1.1 Table 5.6 group (or ASME P-Number), and the thickness range the WPS covers.

Filler metal

AWS A5 specification and classification, electrode or wire diameter, and flux or shielding gas.

Position

Positions the WPS allows, and vertical progression (uphill or downhill) where it applies.

Preheat and interpass

Minimum preheat, maximum interpass temperature, and any postweld heat treatment.

Electrical characteristics

Current type and polarity, amperage, voltage, wire feed speed and travel speed ranges.

Technique

Stringer or weave bead, single or multiple passes per side, and cleaning between passes.

The variables that matter most are the essential variables: change one beyond its limit and the WPS must be requalified. In AWS D1.1:2025 they are in Table 6.6 (Table 6.8 adds supplementary ones when CVN toughness testing applies). ASME Section IX splits them into essential, supplementary essential and nonessential (see the three variable types).

AWS D1.1 gives two routes. A prequalified WPS (Clause 5) needs no test weld, as long as every condition holds: an approved base metal from Table 5.6, a matching filler, a prequalified joint detail from Figures 5.1 (CJP), 5.2 (PJP) or 5.3 (fillet), at least the Table 5.11 minimum preheat, and a prequalified process. See prequalified base metals.

Step outside any of those limits (an unlisted steel such as A514, short-circuit GMAW, a non-standard joint) and the WPS must be qualified by test under Clause 6: weld a test coupon, run the required tests and record the results on a PQR. ASME Section IX has no prequalified route. The full process is in how to qualify a welding procedure.

A WPS for the most common shop weld: A36 plate · SMAW E7018 · single-V groove. This is the output of the free editor's rule tables, before a CWI confirms the joint detail, completes the identification block and signs.

Rule library based on AWS D1.1:2025. Verify against your governing edition (the AHJ or contract may specify 2020 or earlier). Parameters are typical shop starting points, not code-mandated values.

1. Pick the governing code from the contract: AWS D1.1, D1.5, D1.6, ASME Section IX or another.
2. Decide the route. If the base metal, filler, joint, preheat and process all fit Clause 5, write it as prequalified. If not, plan a PQR test.
3. Fix the base metal and thickness range. Look up the Table 5.6 group; it drives filler matching and the preheat category.
4. Choose the filler that matches the base metal strength, and the gas or flux for the process.
5. Set preheat and the electrical ranges. Preheat at or above Table 5.11; amperage, voltage and travel speed inside the code limits.
6. Check the joint detail against Figures 5.1 to 5.3, and the fillet size against Table 7.7.
7. Review and sign. A CWI or QC manager reviews the WPS, signs it, and it goes to the welders before production starts.

Steps 3 to 6 are table lookups, which is where most errors creep in. The free editor does those lookups for you and flags anything below the code minimum.

What does WPS stand for in welding?

Welding Procedure Specification. It is the written procedure that tells a welder exactly how to make a production weld so it meets the governing code, such as AWS D1.1 for structural steel or ASME Section IX for pressure work.

What is the difference between a WPS and a PQR?

The WPS is the instruction for production welding. The PQR (Procedure Qualification Record) is the record of a test weld: the actual variables used and the mechanical test results. A PQR proves that a WPS works; a prequalified AWS D1.1 WPS does not need one.

Do I need a PQR for every WPS?

Under AWS D1.1, no: a WPS that meets every Clause 5 condition (base metal, filler, joint detail, preheat, process) is prequalified and needs no test. Anything outside those limits must be qualified by test under Clause 6 with a PQR. ASME Section IX has no prequalified route, so its WPSs are supported by PQRs.

Who signs a WPS?

The fabricator or contractor is responsible for the WPS. In practice a CWI or QC manager reviews and signs it, and the contract may require the Engineer to approve it before production welding starts.

Is there a standard WPS form?

AWS D1.1:2025 includes a sample form in Annex J (Form J-1). ASME Section IX provides QW-482 for the WPS and QW-483 for the PQR. The forms are suggested formats; the required content is what the code lists.