Hardnes values

[Merzi]

I am qualifying Low Temp welding procedures with Impact test at -45°F. The required hardness of the weldmetal and the HAZ is max 200 BHN.

My question is do i have to do PWHT to meet the hardness requirement, and what wil be the effect of PWHT on Charpy impact values.

 

[metengr]

You had posted this same question on the end of a thread in the ASME (mechanical) Code issues forum with some additional information - SA 516 material, 1" thick. To meet the HAZ hardness requirement of 200BHN, you will need to PWHT the weld coupon. The affect of PWHT on impact properties is usually beneficial, meaning that you should be able to achieve the impact requirements at -45 deg F. The PWHT will have some affect on the tensile strength of the weld metal, so be aware. With a maximum hardness requirement of 200 BHN, you should be ok.

 

[sitidor]

Also considerlimiting heat inpu, as this may affect hardness.