Effect of Boriding on Bearing Wear and Lubrication.

A study is being made to determine the feasibility of improving the wear and erosion resistance of gun barrels by the use of boride coatings on the steel surfaces. As one part of this work, an experimental investigation was made of the friction and wear characteristics of boride-coated steel sleeve bearings operating in the boundary region of lubrication. Evaluation tests were run at slow speeds under various loading conditions to determine the sliding behavior of plain, borided sleeve bearings running against hardened tool steel shafts. These tests were run under three conditions dry, lubricated with an SAE 10W petroleum oil, and lubricated with an SAE 10W oil which contained known quantities of silica as an abrasive. For comparison, steel bearings which had not been exposed to the boriding process were also evaluated.