SA517B P11B PWHT soak time exceed
SA517B P11B PWHT soak time exceed
(OP)
Hi Frends,
we have new constructed pressure vessel made out of SA-517B which is P11B Group 4 shell thickness 0.370" after vessel been fabricated sent out for stress relieving as per engineers issued PWHT instruction sheet heating time suppose to be 350F/hr and soak time 30 minute at 1050-1100F. We get the vessel back after PWHT came along with PHWT chart which was heating time 150F/hr and soak at 1100F for 7 hours insted for 30 minutes?. Is that acceptable?.
Thank You!
we have new constructed pressure vessel made out of SA-517B which is P11B Group 4 shell thickness 0.370" after vessel been fabricated sent out for stress relieving as per engineers issued PWHT instruction sheet heating time suppose to be 350F/hr and soak time 30 minute at 1050-1100F. We get the vessel back after PWHT came along with PHWT chart which was heating time 150F/hr and soak at 1100F for 7 hours insted for 30 minutes?. Is that acceptable?.
Thank You!





RE: SA517B P11B PWHT soak time exceed
RE: SA517B P11B PWHT soak time exceed
My openion ASME VIII div I UHT 56 set the minimum requirment for 30 min and it does not say for maximum that mean we can go for 7 hrs?. And as per CWB module 8, it never effects on grain boundaries, grain size and mechanical properties as long as not exceeding above its tempring temprature or austenite region and 1100 F is way below than austenite region. Am I righr?
thank you!
RE: SA517B P11B PWHT soak time exceed
RE: SA517B P11B PWHT soak time exceed
RE: SA517B P11B PWHT soak time exceed
In this case, you CANNOT just make a "judgement" or "evaluation". The heat was just about in spec, but the time at this thin a metal was much. much too long. Mentally, you are trying to "justify" the excess time as if it were 35 minutes instead of 30 minutes. Or the temperature actually peaked at 1175 for a few minutes instead of 1100 for 30 minutes.
7 hours is a loooooooooooooooong time that WILL affect crystal growth and crystal size and grain arrangement and every metal property: nozzles, welds, walls, supports, and end caps. Also, if the steel and nozzles and internals were not properly supported during the entire heat treat cycle, they have sagged and drooped because the red-hot metal has little strength against gravity's pull.
You MUST actually test the metal properties on at least three samples that have been equally heated: All three samples (test coupons) need to have representative welds and HAZ included. Be good to have nozzles in one of the samples, but probably not essential.
RE: SA517B P11B PWHT soak time exceed
RE: SA517B P11B PWHT soak time exceed
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Plymouth Tube
RE: SA517B P11B PWHT soak time exceed
RE: SA517B P11B PWHT soak time exceed
RE: SA517B P11B PWHT soak time exceed
RE: SA517B P11B PWHT soak time exceed
RE: SA517B P11B PWHT soak time exceed
RE: SA517B P11B PWHT soak time exceed
Your "vender" is going to say anything. Can say anything. Might say anything.
Submit the samples. Trust the results. NOT the vender.
RE: SA517B P11B PWHT soak time exceed
Or what other test would you recomend?
Thank you!
RE: SA517B P11B PWHT soak time exceed
RE: SA517B P11B PWHT soak time exceed
Then again, once pressurized, the vessel would not explode. Merely "blow up" into a nice round sphere. Then it would nicely tear at the weakest point. 8<)
RE: SA517B P11B PWHT soak time exceed
RE: SA517B P11B PWHT soak time exceed