WPS vs PQR (WPQR)
A WPS tells the welder how to make a weld. A PQR, called WPQR in the EN ISO system, is the record that proves the procedure produces sound welds. A WPS is only valid when it is supported by such a qualification.
The documents
- pWPS – preliminary welding procedure specification: the procedure you intend to qualify.
- WPQR / PQR – the record of the test weld made to the pWPS, with the actual parameters and the results of destructive and non-destructive testing (EN ISO 15614-1, ASME IX QW-200.2).
- WPS – the working instruction for production, written within the range of qualification of one or more WPQRs (EN ISO 15609-1, ASME IX QW-200.1).
- WPQ – welder qualification (EN ISO 9606-1, ASME IX QW-300): qualifies the person, not the procedure.
How they relate
- Write a pWPS.
- Weld a test piece and test it under a qualification standard; the WPQR records the results and the range of qualification (thickness, positions, material groups, heat input).
- Write one or more WPSs inside that range for production.
EN ISO 15607 lists other routes besides a procedure test: tested consumables, previous experience, a standard welding procedure or a pre-production test, each with its own limits.
What goes into a WPS
EN ISO 15609-1 requires, among others: manufacturer, process, joint type and preparation, parent material and group, thickness and diameter range, welding position, filler metal and gas, current type and polarity, run sequence with current, voltage, travel speed and heat input, preheat and interpass temperature, and post-weld heat treatment.
The wps generator (en iso 15609-1) walks through these fields, suggests filler, gas and preheat from the other calculators and exports a PDF with your logo. A WPS made with it is still only valid when it is backed by a qualification and approved by the responsible welding coordinator.
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