Study of the effect of induction surface hardening on AISI 1045 mild carbon steel

The effects of induction hardening treatment on AISI 1045 mild steel were studied. By considering the changes of micro-structure and mechanical properties as well as the related factors of hardening, the optimal processes of induction treatment were investigated. Primarily, the effect of quenching hardening, the hardness distribution, the case depth and their relations to the changes of microstructure were studied by considering the variation of three parameters: the current of coil, the traverse speed of specimen and the gap between the coil and specimen. The experimental results show that the increase of the current of coil and the decrease of traverse speed of specimen both result in the increase of the case depth. And as the size of coil is fixed, the case depth also increases by increasing the distance of the gap. The maximum surface hardness of specimen can be up to 785 HV0.2, which is much higher than that obtained by the conventional quenching processes and is referred to 'superhardness'.