Dissimilar welding of P1 and P8 materials
Dissimilar welding of P1 and P8 materials
(OP)
Dissimilar welding of p1 to P8 materials for a pressure vessel (ASME VIII div.1), plate thickness is 40mm.
(1) If materials are used for pressure parts, what is the preheat temperature I can use? Can I do PWHT for them?
(2) If materials are used for Non-pressure part, what is the preheat temperature I can use? Is PWHT required by code?
ASME VIII div.1 is used for the pressure vessel construction.
Please advise. Thanks.
(1) If materials are used for pressure parts, what is the preheat temperature I can use? Can I do PWHT for them?
(2) If materials are used for Non-pressure part, what is the preheat temperature I can use? Is PWHT required by code?
ASME VIII div.1 is used for the pressure vessel construction.
Please advise. Thanks.





RE: Dissimilar welding of P1 and P8 materials
Comeback with the specific materials and thicknesses.
RE: Dissimilar welding of P1 and P8 materials
RE: Dissimilar welding of P1 and P8 materials
RE: Dissimilar welding of P1 and P8 materials
Pressure containing base metal: 34mm
Non-pressure containing base metal: 48mm
RE: Dissimilar welding of P1 and P8 materials
You have found your preheat requirement answer above for pressure retaining carbon steel material used with similar material or in a dissimilar metal weld (DMW) joint application (See Table UCS-56 in Section VIII, Div 1). The key is to set a maximum interpass temperature of 400 deg F for use in a DMW to avoid exposing the P-No 8 to high heat input.
For non-pressure retaining CS material that is welded to non-pressure retaining austenitic stainless steel, this advice would still hold for the CS and thickness. I like to use ASME Section VIII, Div 1 preheat requirements even for non-pressure retaining applications to remain consistent.
RE: Dissimilar welding of P1 and P8 materials
Would you recommend the PWHT for the non-pressure carbon steel? Is ASME VIII Div. 1 UCS56 applicable for Non-pressure part?
Appreciate.
RE: Dissimilar welding of P1 and P8 materials
RE: Dissimilar welding of P1 and P8 materials
Thanks.
RE: Dissimilar welding of P1 and P8 materials
If the non-pressure part is P-No 1 material and exceeds 38mm in thickness, PWHT would be required. Now, if you are going to be welding this to a P-No 8 base material in a DMW joint, you should butter the P-No 1 weld joint with 309, PWHT the P-No 1 base material after buttering, and complete the weld joint using 308 stainless steel with no PWHT.
RE: Dissimilar welding of P1 and P8 materials
Thanks for you helpful advice.
RE: Dissimilar welding of P1 and P8 materials
RE: Dissimilar welding of P1 and P8 materials
http://www.cspec.com/
RE: Dissimilar welding of P1 and P8 materials