Letter 4092

How to prevent galing on stainless steel bolts & nuts 

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I produce pipe couplings and stainless steel clamps.The bolts which tightnen the products as the nuts are made of stainless steel 304.Ihave problems of galing (cold welding).I would like to know what kind of lubricantI can use (need to be dry ..or dirt will stick to it while installing the product ).I also need the machine or the process to coat it .

Danny Krausz   - Tel Aviv, Israel

To prevent galling on type 3o4 stainless steel we suggest hard chrome plating a deposit of .0003"-.0005" thick.

Stephen C. Ward - - Canada

We use to aply a Teflon coating on the bolts and nuts to prevent galing. It works very well.

Jordi Pujol - COATRESA - Barcelona

I am considering using 304 Stainless steel bolts to connect aluminum (6061) shape to aluminum (6061) plate. In this application I need to minimize the amount of magnetic material inside my vessel and I cannot use a lubricant because the vessel is under a vacuum. I am concerned about galling. Do I have to chrome plate the fasteners? Is this very expensive? Any other options?

Donald Sokol
- Oak Ridge, TN

Two approaches I have heard of is silver plating the bolts or using Nitronic stainless steel, a grade designed to prevent galling.

 
Ted Mooney, P.E.
finishing.com Inc. - Brick, NJ

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