Torque for M24 SS 316 HCS w/ anti-seize?
Torque for M24 SS 316 HCS w/ anti-seize?
(OP)
Need torque value (ft-lbs) for type 316 stainless M24 bolt / nut joint, at 60% yield with anti-seize on threads.
Assumed fastener yield at 50ksi thus 30ksi when tight. Tensile area is 352.5mm^2
Oiled value came out to 276ft-lb (using 1" bolt)
NASA spec for 316 with dry lube is 155ft-lb, but I believe they use the K value for moly in that
I'm still searching for my reference charts, so any help would be appreciated!
Assumed fastener yield at 50ksi thus 30ksi when tight. Tensile area is 352.5mm^2
Oiled value came out to 276ft-lb (using 1" bolt)
NASA spec for 316 with dry lube is 155ft-lb, but I believe they use the K value for moly in that
I'm still searching for my reference charts, so any help would be appreciated!
"If A equals success, then the formula is: A = X + Y + Z, X is work. Y is play. Z is keep your mouth shut."
-- by Albert Einstein





RE: Torque for M24 SS 316 HCS w/ anti-seize?
Friction coefficient for austenitic stainless steels (according to VDI 2230):
0.08 to 0.16 when lubricated with "solid lubricants or waxes; pastes"
0.14 to 0.24 when lubricated with "wax dispersions, pastes"
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Torque for M24 SS 316 HCS w/ anti-seize?
Are those friction coefficients or nut factors? I don't have my VDI copy by me so I can't look it up. If those are not factors they seem pretty low for SS on SS, even if it is lubed. Given the diameter I am guessing that both components wil have cut threads,which can tend to bump the nut factor unless done well.
I don't have data in this size range though, so I can't help much.
Dick
RE: Torque for M24 SS 316 HCS w/ anti-seize?
Those are friction coefficients, not nut factors.
I think those are accurate for rolled threads and MoS2-based lubricants.
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Torque for M24 SS 316 HCS w/ anti-seize?
Torque specs are not an exact science. If it's so critical, why not do some stretch checking.
RE: Torque for M24 SS 316 HCS w/ anti-seize?
RE: Torque for M24 SS 316 HCS w/ anti-seize?
Took a swag based on a few calculations and used 220ftlb for the instruction sheet. Not critical enough to warrant stretch measurements but should be adequate for the application.
Thanks!
"If A equals success, then the formula is: A = X + Y + Z, X is work. Y is play. Z is keep your mouth shut."
-- by Albert Einstein