carlomaderazo;
The minimum hardness value will depend on actual post weld heat treatment temperature and time, and original heat treatment condition of the base metals (annealed or normalized or normalized and tempered).
Assuming you did not exceed the lower critical transformation temperature during PWHT and were above the minimum PWHT temperature required by Code, I have seen hardness as low as 170 BHN in weld metal and surrounding P-No 4 base metals.
