Qualification of a pWPS

Depending on the industry and application, a weld needs to be of a certain quality. This quality is generally defined by different standards and regulations.

It is obvious that the construction of a steel bridge is not subjected to the same standards as the fabrication of a nuclear cooling system. But what if you don’t have the proper WPS at your disposal? It all starts with a pWPS.

What is a pWPS?

The acronym pWPS stands for Preliminary Welding Procedure Specification.

It is the first step towards a qualified weld. Manufacturers of welding equipment usually integrate a certain number of WPS in their power supplies to be used as a base for your work. The welder or welding machine operator selects the preset parameters according to the type of material, the diameter, the types of consumables, etc. At this point it needs to be said that the preconfigured programs on the power supplies are already qualified welding procedure specifications (WPS). But even the slightest changes made to these programs have to be requalified.

Once the welder or welding machine operator has chosen the desired preconfigured program – depending on his training and skills level – he will now alter the different parameters in order to achieve the desired weld quality.


Basically it depends on the clients requirements. Nonetheless, there are different approaches to the qualification of a WPS:

  • Qualification based on tested welding consumables (DIN EN ISO 15610)
  • Qualification based on previous welding experience (DIN EN ISO 15611)
  • Qualification by adoption of a standard welding procedure specification (DIN EN ISO 15612)
  • Qualification based on pre-production welding test (DIN EN ISO 15613)
  • Qualification based on welding procedure test (DIN EN ISO 15614)

 The first step towards a qualified WPS!

The preliminary welding procedure specification (pWPS) is executed and tested.

A pWPS contains the same information as a WPS. During the testing phase, the different parameters such as the current, the tension or the speed are modified one by one. Each modification is meticulously documented. The parameters that have been applied during the welding test as well as the corresponding results are documented in the “Welding Procedure Qualification Record” or “WPQR”.


Based on this “WPQR”, it is possible to elaborate the final welding procedure. That procedure constitutes the “WPS”.

The preliminary welding procedure specification (pWPS) therefore serves as the base for the welding procedure qualification record (WPQR) which is then qualified by an external organization as a welding procedure specification (WPS).

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Écrit par
Thomas Calleja

International Welding Technologist and welding expert.