Welding procedure qualification

Welding procedure qualification PQR
    PQR is a Welding procedure qualification record abbreviation, it is also sometimes written WPQR , usually translated as "welding procedure qualification report." PQR refers to the records of actual welding parameters and the results of non-destructive testing and mechanical performance tests selected in the welding qualification test piece. Since its introduction in the 1970s , it has become an indispensable work procedure in the manufacture, installation and repair of pressure vessels and pressure pipelines, and is the basis for assessing the welding technology level ( qualification ) of manufacturing, installation and repair units . Because of its scientific, reasonable and strict evaluation process, it has also been adopted by industries such as steel structure, storage tank manufacturing and installation. Although the names are somewhat different ( some are called welding process tests ) , the methods and requirements are basically the same.

In the manufacture of pressure pipelines, ships and other products, two forms of welding documents are often encountered, namely welding procedure documents (WPS) and welding procedure qualification reports (PQR) . Welding of domestic and foreign companies codes require welding procedure , to verify the ability to meet the basic corporate standard welded joint ( the minimum threshold indicator ) . Under normal circumstances, the welding procedure qualification by the technical department of the enterprise establishment, according to demand, in accordance with relevant standards such as the United States ASME first chapter Ⅸ, the European EN 288 - 3 and China NB / T47014-2011 and other standards. Compliance with the standard changes of each important parameter, such as welding method, base metal category ( group number ) , preheating temperature, heat treatment temperature, welding heat input beyond the specified range, must undergo welding procedure qualification tests. Due to the numerous process parameters that affect the mechanical properties of welded joints, many companies have accumulated a large number of welding process qualification reports.

A complete welding procedure qualification procedure can generally be divided into five steps: proposing a procedure qualification project; compiling a procedure qualification task book and welding procedure; conducting a procedure qualification test; compiling a procedure qualification report; compiling a welding procedure to guide production. The program is shown in the figure below: 

PQR is a result record at the later stage of welding procedure qualification, which is finally signed and approved by the company's technical department. PRQ is obtained through welding procedure qualification tests ( ie Welding procedure qualification tests) , and its purpose is to: A check the proposed welding procedure ( PWPS) , whether it is operability and rationality; B selection of welding materials Whether it is correct and whether the welding process parameters are appropriate; C Prove that the equipment and personnel of the factory are in good technical condition, have the ability to engage in the specified welding process, and obtain the welding quality that meets the requirements of the standard.