Nut Material

[sks4338]

What's the difference between A194-4 and A194-2H?
Another words, which one do you prefer to use A194-4 or A194-2H, when pipe material is A335-P11 at 470 Deg. C?

 

[NozzleTwister]

A194-4 nuts include Molybdenum and have a higher minimum tempering temperature.

While B31.3 rates both nut materials for use up to 593 deg. C., I'm used to seeing the bolting for A335-P11 piping to be A193-B16 studs with A194-4 nuts for operating temperatures above 400 deg. C.

NozzleTwister
Houston, Texas