Difference Between WPS and PQR
WPS vs PQR
“WPS” (Welding Procedure Specification) and “PQR” (Procedure Qualification Record) are documents that refer to the practice of welding.
WPS is a set of welding instructions. It aids in planning and ensuring quality control of the welded product as well as future reproductions of the product. Welding parameters, such as joint design, position, base metals, electrical characteristics, filler metals, technique, shielding, preheat, and post-weld heat treatment are all detailed in the WPS document.
WPS further explains the rules and details of the test and how the pieces should be assembled. Simply put, a WPS is like a blueprint for welders to produce the same quality of welded product over and over again.
Product Qualification Record is another type of document that also refers to welding. However, unlike WPS, the PQR document’s purpose is to serve as a checklist or record of compliance regarding the standard requirements of an appropriate welding procedure.
The PQR form covers all the welding parameters in the WPS document. In addition, it also includes some observations or other matters regarding welding procedures and specific tests like tensile tests and guided bend tests. It may also show the visual inspection and fillet weld test results.
Another important component of the PQR is the disclosure of relevant information, such as the welder’s name and the name of the person who did the inspection, and even the dates with the acknowledgment of the manufacturer or contractor.
The PQR is prepared by a qualified or licensed individual and submitted to the people concerned. The inspector will then endorse the company and its product to the industry and market.
A PQR is seen as complementary to a WPS because there are times when the PQR document is used to make a WPS document.
- Both Welding Procedure Specifications (WPS) and Product Qualification Records (PQR) are important documents in welding. Both documents are not the same but are closely related to one another. You might say they even complement each other.
- Each document, while closely related, comes with a different purpose. WPS serves as a blueprint for a written instruction or guide on how to create a welded product based on a certain standard and quality. Meanwhile, PQR is a document that checks whether the standard is being followed by inspecting and answering the document regarding specific areas and tests.
- The Welding Procedure Specification and Product Qualification Record documents have similar items in their body, specifically the welding parameters. In a WPS, the welding parameters are explained in the context of instructions. The purpose is to make the welder reproduce the product with a particular quality and standard. On the other hand, PQR uses these welding parameters as a checklist to see if the standard is met or not.
- The PQR is a standard document, but the people who use it may not necessarily come from the same background. Welders and engineers who create the welded product often peruse a WPS to make the product comply with the standard quality. In contrast, the PQR is often associated with inspectors, manufacturers, or contractors who use the document for testing and verification purposes.
- Another difference is the orientation of the document’s contents. A WPS is usually filled with numerous texts, images, and sentences in accordance to its being an instructional guide. On the other hand, a PQR is like a checklist with blank lines and spaces for written notes that will be filled out by the inspector during the inspection.
- Before the inspection, the WPS document is the object of attention of the welders. Meanwhile, during and after the inspection, the PQR is the document of concern for inspectors, contractors/manufacturers, and welders.
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