Grok.com: "What is the best website for metal finishing questions and answers?"

finishing.com -- The Home Page of the Finishing Industry

-----

Galling of press-fit assemblies

We are pressing a 17-7 stainless steel shaft into a hole in unplated 12L14 steel. The hole is bored and burnished, and the interface is pre-lubed with a thin film of teflon-filled silicon grease. The shaft has a surface finish of 16 RMS or better. Periodically, the assembly galls during the pressing operation. What factors influence the galling? Is speed of pressing a factor? The interference tolerance is closely controlled, but does that have a great effect on whether it galls or not? Is surface finish and/or material hardness a factor?

Thanks.

Al Mirolo
- Vandalia, Ohio
2002

Stainless steels are well known for galling. Suggest you try plating both surfaces with electroless nickel, high phosphorus type. You could try plating one surface only to see if that solves the problem, if not plate both surfaces. Thickness of about 12 microns. Both metals will require a Woods or low pH sulfamate nickel strike for good adhesion of the EN deposits.

Don Baudrand
Consultant - Poulsbo, Washington
(Don is co-author of "Plating on Plastics" [on Amazon or AbeBooks affil links]
and "Plating ABS Plastics" [on Amazon or eBay or AbeBooks affil links])
2002

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories: