Welding procedure provides a system that is used in welding operation to produced sound weld repeatedly.
It is an essential document for all welding processes. It gives the right guidelines to welding operators for good quality welding. Under the welding process, a variety of necessary processes have been developed that are working in industries today and which will be briefly discussed here.
Basically, the welding procedure made up to control the economical and quality facts.For that purpose, a variety of procedures and standards are used such as:
preliminary welding procedure specification (pwps):-
It is an initial and detailed quality-related document that includes all preliminary welding data prior to approval.All data recorded on this document remains preliminarily prior to the successful completion of any required test or examination.
A WPAR (Welding procedure Approval Record) is a quality document that holds precise data for all essential and non-essential welding variables that were used and recorded for the test weld.
This includes all subsequent data for any PWHT and the results of any mechanical tests performed on the weld.
Welding Procedure Specification (WPS):-
A WPS is a working document that is prepared from the WPAR and then is issued to the welder.
It contains all the essential data required by the production to complete the weld successfully, achieving the minimum level of any properties required.
According to ASME Sec.ix, the purpose of the welding process
(WPS) and process qualification record (PQR)
Determine if the weld proposed for construction is
Able to have the qualities required for your desired
An approved WPS may have an approval limit (tolerance to work) for certain variables, the following of which are possible examples:Thickness of plate,Diameter of pipe,Welding position,Material type/group,Current/Voltage range,Number of passes,Welding consumables,Heat input range,Interpass temperature,Preheat etc.