Overview of residual stresses after induction surface hardening

The paper provides a short survey of the technical literature on induction surface hardening. A general introduction is followed by a description of metallurgical aspects of induction heating, the discussion being focused on the dependence of the heating rate and the temperature required for homogeneous austenitising from the heating time. Particular attention is thus paid to temperature-time dependence in induction surface heating with reference to power density and heating time at a given high current frequency. This is followed by a description of modes of quenching and the related changes of internal stresses and occurrence of residual stresses in modelling and experimental measurement with both heat-treatment steels and case-hardening steels. Finally, the relationship between fatigue strength for finite life and fatigue strength of different steels is shown in relation to different modes of heat treatment.