Understanding Welding Procedure Specifications (WPS) and Procedure Qualification Records (PQR)
By Ken Fields, CET, CWI
Understanding welding procedure specifications (WPS) and procedure qualification records (PQR) is not a complicated task when one understands what they are, the different nomenclatures of a WPS, and how they are developed and support each other and the welding process.
However, before exploring the different nomenclatures of WPS and learning how they work together, let’s define WPS and PQR so we can understand why they are important to get right at the beginning of a project to streamline your next welding inspection.
What is the Difference Between WPS and PQR?
A Welding Procedure Specification (WPS) is a code-required document that outlines the parameters and variables so welders can perform a repeatable weld (with known properties). A WPS includes the welding process and the required base materials, the joint design, geometry, gasses, flow rates (determined by the required weld process), welding positions, process conditions, and variables.
A Procedure Qualification Record (PQR) consists of the actual values recorded during the welding of a test coupon. The PQR documentation verifies that the test coupon has met all code requirements and will be the basis for developing a WPS (or multiple WPSs).
Why Are WPSs and PQRs Important?
WPS are not just roadmaps that provide welders with the proper directions to produce continuous sound welds. A well-developed WPS—and PQR that backs up the WPS—will increase productivity by outlining the most efficient range in welding parameters and variables to maximize production rates. By following the outlined parameters within the developed WPS, you can produce sound welds time after time, thus increasing the weld quality to meet every weld’s acceptance requirements. Following a WPS can also increase production rates and quality of welds, decreasing production costs that lead to increased profits.
You may have heard a variety of terms when it comes to a WPS—a Preliminary WPS, a Prequalified WPS, Standard WPS, or simply a WPS. My next article will provide brief descriptions and use cases for each of these as well as describe how they come into play when developing a qualified WPS.We can help