SA-320 Grade B8M & SA-192 Grade B8M, what is the difference?

[corsa007]

Can anybody tell me the difference between bolting materials SA-320 B8M and SA-192 B8M.

I am aware that SA-320 is for low temp operation but they both have exactly the same chemical composition and maximum stresses. Why is SA-320 B8m limited to a maximum temperature of 38C. It is difficult to understand how a stainless steel would fail at this temperature but this is what the code implies.

Would a bolt designated as A320 also be certified as A192?

Thanks

 

[metengr]

You mean SA 193. Slight difference is in Class designation between SA 193 B8M and SA 320 B8M. The service temperature limits really apply to the ferritic bolting materials because these have a ductile to brittle transition temperature. The austenitic materials have no such transition, and thus could be used in low and higher temperature service.