The Effect of Size on the Distortion Behavior After Carburisation and Quenching Processes of Gears

Abstract

The carbon concentration distribution, temperature history, phase compositions, stresses, and deformations as a consequence of a carburization and oil quenching process, can be modelled by a diffusion Finite Element model followed by a coupled thermo-metallo-mechanical Finite Element model. The aim of current research is to investigate the effect of size of the component on the final distortion behaviour. Therefore the same carburization and quenching processes have been modelled for identical gear components consisting of the same material, and the same geometry but with a length scales differing with a factor 10. The two models incorporate gravity and Transformation Induced Plasticity. The results show a very similar carbon penetration from the outer surface, higher cooling rates in the smaller gear, a higher martensite concentration in the smaller gear, similar distributions and magnitude of residual stresses, but a completely different deformation behaviour.