A Welding Procedure Specification (WPS) is a formal document describing weldingprocedures. The purpose of the document is to guide welders to the accepted procedures so that repeatable and trusted welding techniques are used. A WPS is developed for each material alloy and for each welding type used. Specific codes and/or engineering societies are often the driving force behind the development of a company's WPS. A WPS is supported by a Procedure Qualification Record (PQR or WPQR). A PQR is a record of a test weld performed and tested (more rigorously) to ensure that the procedure will produce a good weld. Individual welders are certified with a qualification test documented in a Welder Qualification Test Record (WQTR) that shows they have the understanding and demonstrated ability to work within the specified WPS.
The following are definitions for WPS and PQR found in various codes and standards:
According to the American Welding Society (AWS), a WPS provides in detail the required welding variables for specific application to assure repeatability by properly trained welders. The AWS defines welding PQR as a record of welding variables used to produce an acceptable test weldment and the results of tests conducted on the weldment to qualify a Welding Procedure Specification.
The American Society of Mechanical Engineers (ASME) similarly defines a WPS as a written document that provides direction to the welder or welding operator for making production welds in accordance with Code requirements.[1] ASME also defines welding PQR as a record of variables recorded during the welding of the test coupon. The record also contains the test results of the tested specimens.
In Europe, the European Committee for Standardization (CEN) has adopted the ISO standards on welding procedure qualification (ISO 15607 to ISO 15614) and on welder qualification (ISO 9606), with the exception of qualification for steel welders, where a new version of the old european EN 287-1 standard still applies. EN ISO 15706 defines a WPS as "A document that has been qualified by one of the methods described in clause 6 and provides the required variables of the welding procedure to ensure repeatability during production welding". The same standard defines a Welding Procedure Qualification Record (WPQR) as "Record comprising all necessary data needed for qualification of a preliminary welding procedure specification". [2] In addition to the standard WPS qualification procedure specified in ISO 15614, the ISO 156xx series of standards provides also for alternative WPS approval methods. These include: Tested welding consumables (ISO 15610),Previous welding experience (ISO 15611), Standard welding procedure (ISO 15612) and Preproduction welding test (ISO 15613).
In the oil and gas pipeline sector, the American Petroleum Institute API 1104 standard is used almost exclusively worldwide. API 1104 accepts the definitons of the American Welding Society code AWS A3.0.[3]
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