Welding P5A to P8 1

[iam42]

Does anyone have suggestions on welding P5A to P8. PWHT will be required. Welded in accordance with B31.1.

I am think about buttering the pipe end with ErNI-3 and PWHT the pipe end. Complete the joint with 309.

Any opinions would be appreciated

Thanks

 

[metengr]

This is correct. The only question I have is the service temperature of the DMW.

If the service temperature is at or above 800 deg F, go with Inconel all the way out in lieu of 309. Yes, 309 will work, however at service temperatures above 800 deg F a damage mechanism called carbon migration (or diffusion) along the P-5A side of the weld joint will result in increased susceptibility to creep failure.

 

[iam42]

Thanks Metengr,

The service is 998 F, So I will follow your valuable advice and go with the inco all the way.