Welding procedure qualification

Welding procedure qualification is the activity, not a single document: it is what has to happen before a WPS can be trusted, and what a PQR is the record of once it has happened. The three names cover three different things — an activity, an instruction, and a record — and confusing them is the most common way a qualification file turns out incomplete on audit.

The sequence runs in one direction. A welding engineer or coordinator drafts a preliminary welding procedure specification (pWPS) — the same content a WPS carries, but not yet proven. A test weld is made to that pWPS, examined and mechanically tested exactly as the applicable code requires, and the results, recorded together with the parameters actually used, become the PQR (ISO code families call the equivalent record a WPQR). Only once that record exists can the pWPS be reissued as a qualified WPS, and only for the range of materials, thicknesses, processes and positions the test weld actually covered — the qualification does not retroactively validate a document written before the test, it replaces it.

Who signs off differs by code family, and the general shape is worth knowing before assuming one pattern covers both routes named above: under the ISO 15614 series the test is typically witnessed and the resulting WPQR countersigned by an examiner or examining body, coordinated through the welding-coordination role ISO 14731 defines; under ASME Section IX the manufacturer’s own qualified personnel certify the PQR as part of the manufacturer’s own quality system record, without a mandatory third-party examiner in the base requirement. Confirm which route a specific contract invokes rather than assuming either pattern — ISO 15607 is where the choice among qualification routes is actually made.

Nothing about the sequence is one-time. Move an essential variable — the exact list is set by the governing code and differs by process — far enough outside the qualified range, and the WPS built from that PQR no longer covers the job in front of you: a new qualification test, or a formal extension the code recognises, comes before the WPS is revised. A procedure qualification also says nothing about the person executing it, which is the separate, independently tested scope of welder qualification.