Stress relief include in PWHT 2

[roniprabowo]

Dear all,
I have carbon steel shell with 60 mm which is mandatory for PWHT. In other hand we also require stress relief because of extreme fiber elongation excedd 5% during forming.
Can I include stress relief in PWHT for this shell ? In other word there is only one heat treatment.
Looking forward for your information.

 

[PAN]

In case of mandatory PWHT at approx 600 C. No need to specify stress relief again.

 

[JoeTank]

I don't have my ASME VIII Code available to me at this momoment to verify this, but I believe that the Code requires the part to be normalized if the extreme fiber elongation exceeds 5%. ASME PWHT min temperatures will not likely get you into the normalization range of temps. So, I'm not sure that the PWHT will satisfy both requirements of the Code.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[deanc]

UCS-79 sends you back to UCS-56. See UCS-56(b) which may allow for higher temperatures. Suggest you read all paragraphs carefuly.

 

[JoeTank]

deanc,
You're right... nothing better than reading what the Code really says. Again, I working from memory (w/o a Code), but if the PWHT is taken above the lower transformation temperature there are additional Code requirements for the WPS/PQR found in ASME Section IX. Am I correct?

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[deanc]

Yes,this may apply per ASME SecIX QW-407.1. Very imortant consideration.

I try not to work from memory as I am wrong about 50% of the time. Have CRS.

 

[jamesl]

PWHT according to UCS-56 will satisfy UCS-79. One heat treatment is enough. See code interpretation VIII-1-95-50.

 

[jorgebaor]

Steel St 60-2 what is your similar on AISI Code?

 

[carljpme]

Yes, PWHT can cover code requirement for P-1 material above 1.5" and satisfy the stress relief requirements for fiber elongation.

 

[ab1234]

Only one heat treatment required in this case. As per UCS-79 P-1, G-1 material are exempted upto 40%fibre elongation (subject to conditions). Since in your case thickness is 60mm, you need to carry out one heat treatment.
This heat treatment can be clubbed with final vessel PWHT.