Bending fatigue and contact fatigue characteristics of carburized gears

Abstract In order to assure reliability, the manufacture of gears for power transmission in high load bearing applications requires precise control of a wide range of processing parameters during manufacture, aimed at achieving specific material properties. Process selection and control in forming and heat treatment operations plays a crucial role in gear production, and must start at the design stage. Material selection, choice of forming processes, thermochemical and heat treatment operations, surface finish and condition will ultimately determine the integrity and performance limits of the gears. An ongoing research programme by Birrana Engineering, Adelaide, and the University of South Australia involves the evaluation of materials, process route and process control used in the manufacture of a range of gears and relates these factors to fatigue resistance, with the aim to reduce production costs and improve gear quality and reliability. The results of single tooth bending fatigue, and contact fatigue tests on production gears manufactured from EN39B steel (steel A), and experimental steels B, C and D (heat treatment details restricted for commercial reasons) are presented and discussed.