Effects of Gear-Side Case-Hardening on Residual Stress of Case-Hardened Gears.

Abstract

This paper presents a study on effects of gear-side case-hardening on residual stresses of case-hardened gears. The carbon content of each element of the FEM models due to carburizing was computed on the basis of the relation between carburizing condition and carbon content distribution. A heat conduction analysis and an elastic-plastic stress analysis during the case-hardening process of spur gears were carried out for various case-hardening conditions by the three-dimensional finite-element method (3D-FEM), considering changes of the thermal expansion coefficient and the yield stress with the temperature and the carbon content distribution, and then residual stresses were obtained. The effects of the case depth, the case-hardened part (tooth surface, gear-side and bore), the face width, the rim thickness and the standard pressure angle on the residual stress were determined.