PWHT of thin 2.25Cr-1Mo parts 2

[WeldUK]

Hi all, I have come across a spec that requires PWHT based on material grades (P-Nos), regardless of thickness. This is likely to give distortion problems when welding thin components (1/8in or similar) made of F22. On the other hand, we risk failing the hardness test, if we try to qualify procedures for F22 without PWHT.

Can anyone share their thoughts?

 

[metengr]

I don't see any problems with welding thin section 2.25%Cr-1% Mo with a generous preheat of 400 deg F and no PWHT. Without knowing the maximum hardness for your application, I can't speculate on pass or fail.

 

[weldstan]

What is your hardness limit? For 1/8" thickness, hardness below 240 HV is readily obtainable with 400 F preheat and slow cooling under insulation blankets immediately after welding.

 

[WeldUK]

Thanks guys, this is very useful. Hardness max 350HV so we should be fine.