tungsten disulphide as an anti-galling agent on stainless steel 3

[DAZCABS]

I am trying to find a relatively cheap and easy method of stopping galling occuring on two mating parts made of the same grade of stainless steel. There are no moving parts in the connection but they are subjected to high pressures. It is only apparant when we come to service the parts and try to seperate them, galling has occured. We stopped the problem with electroless nickel plating with ptfe particles but it is an expensive operation. A number of ideas i have come accross are interesting, these being:- tungsten disulfide powder, can be polished into the surfaces of mating parts or air blasted onto mating parts, apparently completely eradicating galling, also using slightly different grades of ss will help. Does anybody have any info to verify the introduction of these operations and if so where i can purchase them from. Cheers

 

[unclesyd]

I currently have some test underway using WS2 to eliminate a stick slip problem with the subsequent wear and galling of SS components. I am also evaluating Boron Nitride (BN). Both of these material have given a significant improvement in operation but the jury is out on which is the better.

Here are two suppliers of WS2

http://www.rosemill.com/default.asp?pageid=27390

http://www.dynacron.com/index.html

Here is a supplier of BN coatings

http://www.zypcoatings.com/ProductPages/BnCoatings.htm

You need to look a SS material like Nitronic 60 or Gall-Tough as mate for one of your components. Both materials are inherently non galling and exhibit good wear properties while maintaining good corrosion resistance.

 

[JTreglio]

There are companies that can deposit tungsten disulfide by PVD processes. This gives the material very good adhesion to the substrate and much better performance overall. Might also try molybdenum disulfide -- very similar in performance, with a somewhat lower friction coefficient, but less expensive.

Jim Treglio

 

[ballvalveguy]

The problem with stainless steel is it has a low galling threshold. If you harden the surface, that will increase the galling threshold, and prevent it from galling. There is a diffusion process for stainless steels that is proprietary to bodycote. It is relatively inexpensive and will solve your galling problems. Contact mike.johnston@bodycote,com and he will be able to help you out.