Galling with Stainless Fasteners
Galling with Stainless Fasteners
(OP)
Design will use Stainless Steel Helical Inserts paired with SHCS. If Stainless Steel SHCS were specified, there would need to be some Moly Lube, etc to lubricate the stainless on stainless pair which would be an issue... BUT... Design cannot use lube. How about a Steel Alloy cap screw? Assumption is zero galling worry and pick up about 20 ksi tensile on the fastener... Only disadvantage is not as corrosion resistant as Stainless...
Please give comments on galling... Thanks.
Please give comments on galling... Thanks.





RE: Galling with Stainless Fasteners
Can you use sealant, like Loctite Pipe Sealant with Teflon?
It lubricates screws during assembly, then cures in place and doesn't migrate. It locks the screw in place, but doesn't require heat for removal. Works great with alloy SHCS, and protects them from corrosion if you use a lot. Downsides to using that much; you get to wipe off a lot of excess, and the smell can get annoying.
Failing that, you have a universe of materials available other than stainless for whichever part is not stainless, subject to environmental and other factors not stated.
Mike Halloran
Pembroke Pines, FL, USA
RE: Galling with Stainless Fasteners
There have been lots of threads on galling, maybe one of them will give you what you're after.
http://www.eng-tips.com/search.cfm?pid=404&act...
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Galling with Stainless Fasteners
RE: Galling with Stainless Fasteners
RE: Galling with Stainless Fasteners
http://www.stanleyengineeredfastening.com/sites/ww...
RE: Galling with Stainless Fasteners
RE: Galling with Stainless Fasteners
We use helical thread inserts and stainless steel screws almost systematically. We have no problems with galling.
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JHG
RE: Galling with Stainless Fasteners
If you want a readily available cres material for the thread insert and SHCS that will minimize galling, I'd suggest A286. If it is not permitted to use an anti-seize paste/grease, a dry film or silver plating applied to the threads of one part would work quite well.
RE: Galling with Stainless Fasteners
RE: Galling with Stainless Fasteners
2) Consider using larger screws and reducing torque to achieve the same clamping pressure. We use stainless on stainless (304 on 304, 316 on 316) without galling but our torque values are not very high.
3) Consider using another grade of stainless screw. 17-4PH or NAS A286 grade fasteners will be less likely to gall on 300 series base metal. 400 series and Nitronic 60 have their place also - if you can get the inserts in Nitronic 60 you may have solved your problem.
David