hardness across haz of P1-1 to P5a-1 with PWHT to 1250 1

[2minto]

fabricator joined a P1-1 to P5a-1 and completed PWHT to 1250F, B31.1 requires 1300+ for P5a material. ANI approved 1250F at 90 minutes soak, ramp was good.
I would like to confirm that joint is stress relieved can I use harness to confirm ?
Is there a reference of what to expect what hardness from base across the HAZ ?

 

[metengr]

There is no direct correlation between residual stress from welding and hardness. You can use hardness testing as a quality check regarding tempering of the weld deposit and surrounding base material. I would expect hardness values for P-No 5A base metal HAZ of around 270 BHN or less (based on current max of 241 BHN in ASME B31.3 for 1300 deg F PWHT). Keep in mind that hardness results will vary as you progress from the WM to the BM (away from the HAZ).


At 1250 deg F, you should have adequate stress relief for even P-No 5A base materials.