Re: [alfa] Re: SS bolts galling

[Mark Denovich <denovich@xxxxxxxxx>]

Jay Mackro wrote:
> My question for all you metallurgists out there is: Does stainless
> steel tend to "gall" or otherwise  lock up, especially when exposed
> to heat?  Should I have used oil, anit-seize, or some other lubricant
> on the threads (of course, would that have survived the heat of the
> exhaust system?).  I replaced the SS nuts with regular steel ones,
> but retained the SS bolts.  My hope is that this combination will give
> the desired result.

SS definately galls, some alloys moreso than others.  Ti fasteners are
even trickier.   I now use anti-seize or some form of locktite on all
fasteners...  especially when dealing with different alloys (ex: Steel
in Al)   Anywhere you have dissimliar metals together you are setting
yourself up for galvanic corrosion.

Mixing SS and Steel isn't a good idea either.  The iron in the steel
will likely defeat the chromium oxide surface coating that is the key
to stainless steel's stainlessness.   Try using plain steel wool on SS
and watch your shiny SS start to rust.

quick links:
http://www.corrosion-doctors.org/Aircraft/galvdefi.htm
http://chemistry.about.com/cs/metalsandalloys/a/aa071201a.htm

--Mark
The Alfa Wiki: http://alfa.denovich.org
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided