Our Client has ordered material certified to SS316/316L. The question is: Are we allowed to use the higher stress values of SS316 at fairly high temperatures while enjoying the benefit of low carbon content of 316L?

Anyone is aware of any discussion around this subject?

Any opinion by the members of ASME code committee will be appreciated.

It is my understanding and our company policy that a DUAL rated material such as SS316/316L SHALL meet the the higher stress values of SS316, ELSE it CANNOT be DUAL certified.

I heard that dual certified material would not be permitted for temperatures above 1000°F.

Regards,

One needs to carefully read the notes for B31.3 Appendix A for the specific notes listed for the specific material. For example A 312 TP316 note 28 ...>538 C (1000 F), these stress values apply only when the carbon content is 0.04% or higher.

Bob, thanks for your answer.

For argument's sake, if the certification is based on Yield and Tensile at ambient temperature and the supplier has not performed any tests at elevated temperature how do we justify the higher stress values at elevated temperature, say 700 deg.F ?

That brings the other question: Are the stress values in the code are totally based on test results or extrapolation is used to some extent?

Comments will be appreciated.