Hydro-Test for P91 Pipe Spool

[iam42]

I have to Hydrotest a heavy wall (1.38") P91 pipe spool.

I have elliptical heads that are perfect in size for this but they are made from 516-70.

Does anyone see any problem in welding these CS heads to the Grade 91 pipe material. The weld will be PWHT'd and I have checked that the CS material with not exceed 90% yield during the hydrotest. After hydro, the heads will be removed and the weld preps will be machined back on the Gr. 91 pipe.

thanks

 

[weldstan]

Weld with B9 filler to assure that no carbon or lower alloy material remains in place after cutting and machining. Etching is also recommended to assure removal of weld and HAZ.

 

[iam42]

Thanks Weldstan, I will be using a B9 filler and the cut will be made approximately 4" from the weld when removing the head. The weld prep for the Gr.91 pipe will then be machined.

Thanks Again