Flank-Load-Carrying Capacity of Case Hardened Gears With Grinding Burn

Abstract

A high geometric accuracy of case-hardened gears requires a grinding process after heat treatment. Inappropriate grinding conditions can induce surface tempering, alter hardness and lead to an unfavorable residual stress state. This effect is commonly known as grinding burn. The influence of grinding burn on the flank-load-carrying capacity was systematically investigated within a research project. The results of experimental tests and the analysis of surface and near subsurface parameters allowed a correlation between grinding burn grade, material characteristics and flank-load-carrying capacity. A main result of this project is a proposal for the calculation of surface durability of gears which implicates the influence of grinding burn. This paper summarizes results of the experimental testing and the accompanying analyses. The main focus herein is the consideration of an altered hardness and residual stress state in a material-physically based model for calculating the load capacity of gears.