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Galling, cold welding of bolt to nut
Q. Facing galling problems with assembling stainless steel 304/316/316l bolts/nuts of same materials. It is difficult to remove nuts from bolts after checking assembly. Nuts gets fixed with bolts & to remove, cutting bolts remain only alternative. These spoils bolts/nuts & have to make new sets. costing increases. Please advice to solve problems.
TUSHAR DESAImfg. of stainless steel fasteners - MUMBAI, MAHARASHTRA, India
2004
A. Try using Teflon pipe dope. It is made for sealing pipe threads, but it is a readily available material that can be used as an anti seize material.
James Watts- Navarre, Florida
2004
June 30, 2011
Q. Dear Sir / madam
I read your newsletter in the internet and I found the knowledge provided by you is excellent.
We are a small scale industry manufacturing "Fasteners in Stainless Steel" in India by hot forge process.
Sir, we have a question: recently we supplied fasteners to a power plant and they used them to fit the flanges and pipes.
However the Flanges and Pipes are of carbon steel, while fasteners supplied by us are stainless steel ASTM A193 B8M bolts and ASTM A194 8M nuts ( SS316 ).
The fasteners supplied by us , some of them were manufactured in cold forge process while other sizes were manufactured in hot forge process
All material has been checked, chemically and physically tested, and found ok
The Bolts are fitted with the help of spanner at the site and are fitted manually by the worker;
the problem facing the site is that once the bolts are fitted, if they want to remove it, out of every 8 bolts , around 2 pieces - 3 pieces get stuck and cannot be removed
and then they have to cut the bolts.
Can you advise where can be the problem?
Please provide some suggestion and solution to this matter.
Regards,
owner - India
A. Silver plating of either the nut or bolt will eliminate the problem.
Jeffrey Holmes, CEF
Spartanburg, South Carolina
July 1, 2011
A. Silver plating of the bolt is a great way to go. Teflon tape or paste will work fine also. Tin or solder or any soft metal will also work in most cases and is cheaper. Plain old Vaseline will go a long way towards preventing the galling. You need to reapply this each time it is assembled.
James Watts- Navarre, Florida
July 5, 2011
Q. We have a toilet seat with brass fittings that are corroded on. We want to replace it, so we don't care what happens to the brass -- how do we get the fittings to loosen up enough to remove? Can't soak them, obviously.
Lynn Hirshman- Black Hawk, Colorado
June 1, 2015
A. Hi Lynn. Try WD-40 [on eBay or Amazon] or Liquid Wrench [affil links]. Usually they come with a thin "straw" so you can spray the threads and corroded area specifically. Then you tap the bolt a few times to help spread it, apply again and wait an hour. A bigger and tighter-fitting tool will probably help.
But sometimes you are still stuck with cutting the bolts with a hacksaw or grinding them away with a Dremel [on eBay or Amazon].
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 2015
A. Dear Sirs, I read your question about galling and cold welding of austenitic stainless steel bolts. Have you ever considered "low temperature nitriding of stainless steel". it is a bit new surface treatment developed for stainless steels. I am not sure if it is like ordinary nitriding processes but I think it works since it dramatically reduces the friction coefficient.
Farzad HamdiCBG - Tehran, Iran
May 13, 2019
Thanks cousin.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
May 2019
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