Eng-Tips’s functionality depends on heat treatment furnace design pdf receiving e-mail. By joining you are opting in to receive e-mail.
This is long case but I will really appreciate your expert opinion on this. Question: By what temperature can the vendor deviate in their WPS? I believe as long the temperature is approx 50 deg. PQR coupon was 38 mm and it was heat treated for 4 hours 45 minutes.
The WPS says PWHT holding time to be 4 hours 45 minutes to 5 hours 55 minutes. I believe the PQR coupon was required to be post weld heat treated for only 2 hours. The extra 2 hours 45 minutes might be a compensation for the repair welding. The vendor has used the WPS to weld a coupon 3 inch in thickness. The job was then heat treated for 5 hours.
There was a repair in the weld after PWHT which was removed and re-welded. Question: What should be the holding time for the second post weld heat treatment cycle? Will the final repair welding still be acceptable as per the qualified procedure? If not how can it be qualified?
I think the vendor should weld another coupon of 38 mm thickness and post weld heat treat if for 10 hours. Perform tensile test to ensure that the material still has the required tensile properties. Yes, or if the construction code requires a specific minimum to maximum PWHT temperature range. Was the above qualified with impact testing? The extra time for PWHT is typically for notch toughness properties because notch toughness may degrade over extended PWHT time. This is why I asked about impact testing.