WPS experation date

[mrmalcolm]

There is no expiration date for any WPS or PQR. However, what is the technical background of this?
I understand that a PQR is a permanent record of variables used to qualify a welding procedure and no time limitation for PQR.
However, why is the welding process qualification according to the old ineffective still valid after the new standard comes into effect?
For example, after the release of ISO 15614-1:2017, the WPS qualified according to ISO 15614-1:2004 are still valid. However, compared to ISO 15164-1:2004, ISO 15164-1:2017 has undergone significant changes in examination, testing and range of approval. “Old” WPS does not meet the technical requirements and acceptable weld quality of ISO 15164-1:2017.
It is more appropriate that PQR remains valid, and after the release of the new standard(ISO 15614-1:2017), the essential parameters of WPS are checked to ensure that they meet the new standard. If they do, a new WPS will be directly formed based on PQR.
If there is a change in any essential parameter, then the WPS becomes invalid and has to be requalified or carry out additional tests on a test piece which should be made in accordance ISO 15614-1:2017.

Thanks.

 

[DekDee]

A PQR never expires.
If WPS requirements are superceded by a new edition you rewrite your WPS.
If testing requirements are changed and become additional you perform those tests and add to your PQR.

 

[EdStainless]

This is similar to manufacturing processes.
No quality system has requirements for updating them.
But if the applicable specification change then they need to be revised.