Welding Procedure Specification

The Welding Procedure Specification or WPS is a document that is used to describe welding procedures.  The objective of this document is to inform welders of the accepted procedures to insure that repeatable and proven welding techniques are used.  A Welding Procedure Specification is developed for each metal alloy and for each welding technique used.  A Welding Procedure Specification is also used to explain specific codes or engineering techniques that a specific company uses.

A Welding Procedure Specification is often accompanied with a Procedure Qualification Record or PQR or WPQR.  A Procedure Qualification Record is a record of a test weld that was performed to insure that the technique will produce a weld of high quality.  Individual welders are required to be certified with a qualification test documented in a Welder Qualification Test Record that proves that they have the knowledge and skill to complete the work within the specified Welding Procedure Specification.

In accordance with the American Welding Society a Welding Procedure Specification should provide a detailed description of the necessary welding variable for a specific application to assure its repeatability by skilled welders.  The American Welding Society clearly defines that a Procedure Qualification Record be a record of welding variables that are used to produce an acceptable weld test and that the results of tests on the weld can be used to qualify a Welding Procedure Specification.

The American Society of Mechanical Engineers also defines a Welding Procedure Specification as a written document that will provide directions to the welder or welding operator to properly produce welds in agreement with the Code requirements listed in the Welding Procedure Specification.  The American Society of Mechanical Engineers also clearly defines a welding Procedure Qualification Record as a record of variables that were recorded during the welding of the test weld.  The record should also contain the results from the test weld.

For welders who are working overseas, the European Committee for Standardization or CEN, has adopted the ISO standards regarding the procedure qualification and on welder qualification with the only exception being for the qualification of steel welders.  The European Committee for Standardization states that a Welding Procedure Specification is a document that has been proven by testing one of the methods described in clause six and provides the necessary required variables of the welding procedure to insure its repeatability during production welding.  The same standard is also used to define a Welding Procedure Qualification Record or WPQR as a record that includes all of the necessary data required for qualification of a preliminary welding procedure specification.  In addition to the standard Welding Procedure Specification qualification procedure detailed in ISO 15614, the ISO 156XXX series of standards should also provide for alternate Welding Procedure Specification methods of approval.  These include but are not limited to test welding consumables, previous welding experience of the welder, standard welding procedures and Preproduction welding tests.

In the oil and gas pipeline area, the American Petroleum Institute API 1104 standard is the common method used almost exclusively worldwide.  API 1104 includes the definitions of the American Welding Society code AWS A3.0.  If you require further information on any of these explanations you can contact the American Welding Society for a complete description of what they require to be included in all Welding Procedure Specifications and Procedure Qualification Records.  They will be able to provide all of the necessary information that you require to better understand the guidelines and requirements of these documents.  These documents were designed to provide welders with a clear understanding of the procedures to be followed and proof that the technique will work adequately.

Reference:  http://en.wikipedia.org/wiki/Welding_Procedure_Specification