WPS & PQR

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

Essential variable:  

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.

 

Keep reading, Happy welding

Thank you,

KP Bhatt

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