J. Phys. IV France
Volume 120, December 2004
Page(s) 489 - 497

J. Phys. IV France 120 (2004) 489-497

DOI: 10.1051/jp4:2004120056

Simulation of carburizing-quenching of a gear. Effect of carbon content on residual stresses and distortion

R. Mukai and D.-Y. Ju

Department of Materials Science and Engineering, Graduate School of Engineering, Saitama Institute of Technology, Fusaiji 1690, Okabe, 369-0293 Saitama, Japan

Predictions of deformation, residual stresses and hardness after heat treatment of gears by numerical simulation are very useful to determine optimum condition to decrease the distortion of machinery parts. In this paper, simulation on carburizing quenching of a helical gear made of carbon steel SCr420 was carried out using three-dimensional coupled analysis based on thermo-mechanical theory considering phase transformation. The expansion and latent heat due to phase transformation at various carburizing conditions were measured by TMA and DSC to determine the thermal physical properties of SCr420 carbon steel. The influence of the transformation plasticity strain on deformation, residual stress and hardness of a gear was clarified in the simulation. The accuracy of simulation also is verified by the comparison between the experimental data and the simulated result of the distortion and residual stress. From the predicted results, improvement of the hardness and strength on surface of the gear due to the carburizing-quenching process can be verified.

© EDP Sciences 2004