ASME B31.3 Unlisted Material

[FSB01]

Material SA-484-303 is not lited in B31.3
What are the bases for the design stresses calculation?

Only thing that I have is MTR with Tensile and Yield at room temp. My design condition is 150°F.

Any help is welcome.

Thanks

 

[metengr]

Your question is rather confusing. ASME SA 484 is a Specification for General Requirements for Stainless Steel Bars, Billets and Forgings. I am assuming you are referring to AISI Type 303 stainless? This material is not permitted because it contains increased sulfur to promote machinability and it is considered weldable. Most product forms are rod or bar.

Possible application of AISI Type 303 include Alloy Steel Bolting for Low-Temperature Service ASME SA 320 B8F or nut material under ASME SA 194. ASME B&PV Code, Section II, Part D Table 3 lists allowable stress values for B8F bolting material.

What is your intended application - a hanger support or....

 

[metengr]

Correction to above...it it NOT weldable.

 

[FSB01]

Metengr, thank you for the reply. You are right, this material is used for a nut. My problem is that I need to use it in B31.3 system and I need to do proper calcs. There are no cross-reference on MTR to Sa-320 BF8. I can not use any other material because this is already fabricated part.

 

[metengr]

What calcs do you need? Typically, nuts are in compression after installation so other than having proper thread engagement with the bolt material and assuming adequate service temperature and environment for selection of proper nut material, I don't see how you need any detailed design calcs.

 

[FSB01]

Well, a nut is engaged with blind end under pressure. I need to calculate the shear stress on the threads. It is like a threaded cap. B31.3 is mentioning unlisted material, however it is not clear (for me, at least) which are design basis.
It is a gas fitting that needs to be registered under B31.3 in Canada.