Abstract: Medium frequency induction heating quenching process with a current frequency of 2500Hz which was used to quench thin ring shape iron-based powder hot-forged sealing ring is described. Inductor is of multiple-winding helix tube shape by using sequential heating procedure. Productivity of this guenching process was higher than that of original salt bath quenching by 1. 2 times,pass ratio of hardness was increased from 95.7% to 99.5%, especially the crack and deformation of workpieces were decreased.meanwhile power was saved by 57%.