Influence of additional surface finishing to the material properties and the flank load carrying capacity of case-hardened gears with grinding burn

The grinding of case-hardened gears after the heat treatment ensures a high quality regarding the gear geometry and tooth surface topography. If the limits of the gear material are exceeded during this process, the mechanical and thermal influence from the grinding operation can lead to tempering effects and re-hardening of the gear teeth. As part of the research project FVA (Forschungsvereinigung Antriebstechnik e.V.) 453 (Schwienbacher et al., 2007), the influence of grinding burn on the flank load carrying capacity has been investigated. As a result, a surface factor has been proposed to allow a consideration of the negative influence on the flank load carrying capacity due to grinding burn. However, for most applications, the flank load carrying capacity of the unimpaired tooth flank must be provided to ensure a safe operation. Within the project FVA 453 II (Koller et al., 2012b), the potential of superfinishing, shot peening and re-grinding, respectively, as a repairing method were evaluated experimentally. The main results of this project will be summarized in this paper.