Protective Atmospheres for High-Temperature Bearing Operation

TO operate ball and roller bearings at high temperatures, the bearing is surrounded with a reducing atmosphere to prevent destructive oxidation. Lubricating films are formed on the bearing surfaces by means of reactive compounds added to the reducing atmosphere.

An Air Force sponsored research program is now underway to develop this method further and to determine the range of conditions where it may be usefully applied. It has been found that the lubricating film-forming reaction will not go satisfactorily with certain metals frequently used in high-temperature bearing construction.

However, bearings constructed of all-ferrous metals do work with this method. To date test runs of 100 hr at 700 F and 22 hr at 840 F have been completed without any signs of impending bearing failure.