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Up Topic Welding Industry / ASME Codes / ASME IX Multiple PQR PWHT Heat Input
- By jrupert (*) Date 03-04-2021 12:55
I have a WPS supported by 2 PQRs that is going through 3rd party review (impacts required).  There is a difference of opinion on the heat input allowed for the WPS.  The governing codes are API6A and ASME IX.  The production material is 1" thick.  I've only posted a minimum amount of information that I think is relevant to this situation of heat input.  All other variables are constant.  The first PQR PWHT is 4 hours and the second PWHT is 8 hours.  The first PQR is supporting the original weld and the second PQR is supporting if we need repairs.  The heat input on the first PQR with 4 hours is 25KJ/in and the heat input on the second PQR with 8 hours PWHT is 35KJ/in.  The WPS has to be supported by both PQRs per API 6A (based on the distinct PWHT times), however, 6A does not address or govern heat input.  So we cannot simply remove the 4 hour PQR from the packet.

We are proposing to use the higher heat input of 35KJ/in on the WPS as we believe this meets the ASME rules for heat input based off the 8 hour cycle that covers any time less than 8 hours (all relevant mechanical properties according to ASME IX are met at 8 hours with the higher heat input)

Note that we would agree that if our PQR with 4 hour PWHT was 35 KJ/in and our 8 hour PWHT was 25 KJ/in, that we would need to limit to 25KJ/in.

Please give an opinion supported by sections or interpretations if possible.  I have found a few that are relevant, but none specific to this situation.  I feel this is relatively clear cut and the higher heat input would be acceptable, however, I am open to other interpretations.  The 3rd party does not agree and requires the lower heat input.
Up Topic Welding Industry / ASME Codes / ASME IX Multiple PQR PWHT Heat Input

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