A Weld Procedure Specification (WPS) is a documented instruction to welding personnel. This documented instruction provides guidance on how to make a weld defect free.
Welding is an imperfect process. Therefore, it is mandatory under most welding standards that a Weld Procedure Specification (WPS) be produced. Welding personnel must also be qualified before welding work begin. The welders must be qualified on a production piece that must comply to a standard.
The WPS is developed from a Procedure Qualification Record (PQR). A test piece is welded, during which all welding parameters and essential variables are recorded. Upon compliance of the test piece, the WPS is then produced. The PQR then serves as a record of the original test and the testing carried out. This proves the integrity of the weld.