Hardness 14 HRC with SA516GR70
Hardness 14 HRC with SA516GR70
(OP)
Hello Everybody,
The NACE require 22HRC maxi to prevent HIC effects on C.S. and the use is to select "soft" material like SA516GR65 to reach this value.
Is it realistic to select SA516GR70 if target for welding hardness is 14HRC after PWHT ?
The NACE require 22HRC maxi to prevent HIC effects on C.S. and the use is to select "soft" material like SA516GR65 to reach this value.
Is it realistic to select SA516GR70 if target for welding hardness is 14HRC after PWHT ?





RE: Hardness 14 HRC with SA516GR70
You can purchase grade 70 with limited carbon content down to 0.23% and equivalent carbon of 0.43%;- the hardness will not be 14 HRC, but will be less than 22 HRC. Any higher carbon, the hardness after PWHT is likely to exceed 22 HRC. That's the reason perhaps to select lower grade, say grade 60, which has a bit less strength, thus the minimum thickness will increase, but you can rest assured that all the other NACE requirements will be met easily. This is a very simplistic way to describe the "NACE" material selection process, but is easy to remember and easy to understand. More carbon, higher hardness.
cheers,
gr2vessels
RE: Hardness 14 HRC with SA516GR70
Be sure to specify that the steel be made to fine grain practice with aluminum additions and that niobium or vanadium additions are not permitted for this purpose.