PWHT of 1.25Cr-0.5Mo and SS welding

[Xeros]

Hi,

I have a 1.25Cr-0.5Mo piping that is welded Stainles steel pipig.

Somebody said that 1.25Cr-0.5Mo shall be PWHT after welding with stainless steel.

Is it right?

If it is right, what kind of procedure shall be followed.
1.25Cr-0.5Mo PWHT procedure? or stainless steel PWHT procedure?


Best regards,

 

[metengr]

Xeros;
What is the specific application, and what is the wall thickness of the piping? Note; you should be following some code of construction (either ASME B31.1, or B31.3 , etc.,)

Post weld heat treatment applies to the 1.25%Cr-1/2Mo (Grade 11), which is a P-No. 4 base material, and not to austenitic stainless steel (I presume you are referring to austenitic stainless steel in the above post), which would be a P-No. 8 base material.

If this is the case, the PWHT requirements for P-No. 4 base material should be followed based on the code of construction for piping. For this material, the wall thickness that would require PWHT is 0.5" (13 mm) or less.

Also, you need to have a qualified welding procedure and suitable filler metal (309 or Inconel). Please come back with more information.

 

[metengr]

Correction

For this material, the wall thickness that would require PWHT is 0.5" (13 mm) or less.

Greater than 1/2" (13 mm) wall thickness would require PWHT for P-No 4 base material, not less than 1/2" (13 mm). Sorry about the confusion.

 

[0707]

The PWHT of P11 depends on the thickness of the pipe. Normally the welding of ss doesn’t require PWHT. In this case my opinion is that the best option is to joint P11 pipe with the SS pipe through flanges connection.

Regards

luis marques