Composition. 8620 alloy steel is composed of (in descending order of percentage) iron, carbon, silicon, molybdenum, manganese, nickel, chromium, sulphur and phosphorus. These ingredient elements must be within certain weight percentages to create the 8620 alloy. It is recommended that the steel be hardened by carburization followed by an oil.

Bearing Materials Tables 13.5and 13.6give the chemical composition for these representative cage materials. Besides high-strength brass, medium carbon nickel, chrome and molybdenum that has been hardened and tempered at high temperatures are also used for bearings used in aircraft.