Scope of WPS and PQR
A Welding Procedure Specification (WPS) is written qualified welding procedure prepared to provide direction for making production welds to code requirements.A Procedure Qualification Record (PQR) is essentially a record of welding data used to weld a test coupon. It contains the test results of tested specimens. Recorded variables normally fall within a small range of the actual variables that will be used inproduction welding. Changes to PQR are generally not permitted except in the cases of editorial correction to the entries or the case of an addenda being added. All changes in PQR would call for a requalification. When more than one welding process or filler metal is used to weld a test coupon the deposit weld metal thickness of each process and filler metal would be recorded. Several WPS, may be prepared from the data on a single PQR (eg. a 6 G plate PQR may support WPS for the F, V, H and 'O' positions on plate or pipe within all other essential variables). A single WPS may cover several essential variable changes as long as a supporting PQR exists for each essential and supplementary essential (when required) variable (eg. a single WPS may cover a thickness ranging from 1.6 mm through 32 mm if PQRs exist for both 1.6 mm and 5 mm through 32 mm thickness ranges).