Monel 400 stud 3

[Marke525]

I have a customer who requires studs to meet SA-193 (Grade B7) , we currently use Monel 400. From what I've been able to find out this material is not SA-193, but does it exceed SA-193? And if so is it generally an acceptable practice to substitute a higher grade material for SA-193?

 

[kenvlach]

No (& don't presume which material is superior, either).
See ASTM A193/A193M, 'Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for High Temperature or High Pressure Service and Other Special Purpose Applications.'

http://www.astm.org/cgi-bin/SoftCar...EDLINE_PAGES/A193A193M.htm?L+mystore+lvay6422

Monel 400 might have better corrosion resistance in some applications at lower temperatures, but A193 is a specification for high temperature material. The Monel 400 may anneal, weaken & fail in use.

 

[EdStainless]

No, you can't substitute without permission.

Give them the SB spec that your studs meet and the properties and let them decide.

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Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[metengr]

Since you referenced an ASME Material specification in lieu of an ASTM Standard Specification, I would strongly suggest you review ASME Boiler and Pressure Vessel Code, Section II, Part D for allowable bolting materials, and corresponding allowable stress values.

Monel bolting is listed under ASME SB 164, and is limited to service temperature at or below 900 deg F depending on condition and use in service. So, read up.