COMPARISON OF PITTING FATIGUE LIFE OF AUSFORGED AND STANDARD FORGED AISI M-50 AND AISI 9310 SPUR GEARS

摘要

Standard forged and ausforged spur gears made of vacuum-induction-melted, consumable-electrode, vacuum-arc-remelted (VIM-VAR) AISI M-50 steel were tested under conditions that produced fatigue pitting. The gears were 8.89 cm (3. 5 in.) in pitch diameter and had tip relief. The M-50 standard forged and ausforged test results were compared with each other. They were then compared with results for machined vacuum-arc-remelted (VAR) AISI 9310 gears tested under identical conditions. Both types of M-50 gears had lives approximately five times that of the 9310 gears. The life at which 10 percent of the M-50 ausforged gears failed was slightly less than that at which the M-50 standard forged gears failed. The ausforged gears had a slightly greater tendency to fail by tooth fracture than did the standard forged gears, most likely because of the better forging and grain flow pattern of standard forged gears.