Improvement in Surface Fatigue Life of Hardened Gears by High-Intensity Shot Peening

Author:  Townsend, Dennis P.
Source:  NASA Tech Report 91-C-042, ASME, 6th IPTGC Society of Mech.
Doc ID:  1992032
Year of Publication:  1992
Abstract:  
Two groups of carburized, hardened and ground spur gears that were manufactured from the same heat of vacuum-induction-melted-vacuum-arc-remelted(VIM-VAR) AISI 9310 steel were endurance tested for surface fatigue. Both groups were manufactured with a standard ground 16-rms surface finish. One group was subjected to a shot peening intensity of 7 to 9a, and the second group was subjected to a shot peening intensity of 15 to 17a. All gears were honed after shot penning to a surface finish of 16 rms. The gear pitch diameter was 8.89 cm. Test conditions were a maxumum Hertz stress of 1.71 GPa, a gear temperature of 350 K and a speed of 10,000 RPM. The lubricant used for the tests was a synthetic paraffinic oil with an additive package.