A welding procedure specification (WPS) is a written procedure or set of instructions prepared to provide welding parameters for the making of a defect free weld. It can be used on production only after successful qualification of the supporting PQR. A WPS can be supported by one or multiple PQRs. Basically, a WPS allows welders to consistently produce welds that meet desired requirements under the standard or code, without any rework.
Benefits of WPS
- A WPS assists in planning and ensuring quality control of the welded product, and for future reproductions.
- WPS explains in depth the rules and details of the test and how the pieces should be assembled. It acts as a “blue print” for welders for the same welded joint or product.
A Procedure Qualification Record (PQR) is a record of the actual welding data used to weld a test piece. A PQR includes additional observations from what is in a WPS, it records other matters regarding welding procedures and specific tests, for example they may include tensile tests or guided bend tests.
Benefits of PQRs
- PQRs relate to a particular welder and note appropriate information, such as the welder’s name and the name of the person who did the inspection and the dates with the acknowledgment of the manufacturer or contractor.
- A PQR is seen as the mandatory document containing the information that the WPS is based on.
- The PQR records all the information that was used to weld the test piece. The WPS provides ranges based on that information, that a welder can then follow without the need to remain exactly within the same parameters that was used on the PQR.
In simple terms:
The WPS is written from the PQR.
A PQR comes before a WPS.
A PQR is needed to do a WPS.
The PQR is specific while the WPS is generic.