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Galling on Rotating Stainless Flanges

We are having suspected galling issues on a bayonet type locking flange. The flange is similar to a camera lens. These flanges are about 12 inches in diameter and are both made of 316L stainless steel with a #4 ASTM A480 finish. There is an O-ring between the flat mating surfaces which is compressed during the docking of the flanges. Our process will not allow the use of liquid or paste lubricants so therefore we are wanting to operate dry. The seal between the flanges is lube-impregnated silicone, so our only stainless to stainless contacts are the bayonets. As the flange rotates the gasket between the mating faces of the flanges compresses and applied the load on the bayonets. I do not know the actual loads on the bayonets, but they are significant enough to create a helium-tight seal between the flanges.

Any suggestions on coatings and/or alternate materials?

Ben Arnold
Engineer - Oak Ridge, Tennessee
October 28, 2008

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Hi, Ben. Assuming that these are fairly expensive components which would justify it, silver plating one or both sides should solve the galling problem. The area can probably be brush plated if this is an existing installation.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 29, 2008

Ben, I would suggest Electroless Nickel Coating one or both components. We have applied EN to similar stainless components with galling issues. Tim

Tim Deakin
North Tonawanda, New York
October 31, 2008