WPS: Welding Procedure Specification
It is a written procedure prepared to provide welding parameters for making welds as per code requirement. It can be used on production only after successful qualification of supporting PQR. A WPS can be supported by one or multiple PQR.
Contents of WPS: Essential, Non-Essential, and when required supplementary essential variables for each welding process used in WPS
A change in welding condition which will affect the mechanical properties other than toughness of weldment. Any change in this variable calls for re-qualification of PQR
Supplementary – essential variable:
A Change in welding condition which will affect impact toughness of weldment. Change in this variable calls for re-qualification of PQR in case there is requirement of impact toughness for the vessel
Non – essential variable:
No change in mechanical properties is expected. A change in welding condition which will not affect any mechanical properties of the weld joint
A WPS shall record all essential, supplementary essential & non-essential variables.
Change to WPS: Changes in the WPS may be made in non-essential variable to suit production requirements without requalification.
PQR: Procedure Qualification Record
It is a Record of the actual welding data used to weld a test coupon. It also contains test results (Mechanical, Chemical & Non Destructive Test) of the test coupon. One PQR can support one or multiple WPS.
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