Low carbon steel without any alloying elements which enhance the quench hardening has not been considered as a material fitting for quenching. In the present study, however, the quench strengthening was found to occur fully in the sheet of the low carbon steel after the sheet was rapidly cooled in rf induction heat quenching. This finding shows the possibility of a combined process of press forming and quenching. In this process, for example, an automobile part which is press formed severely with the steel sheet of good formability is thought to be increased in strength by the induction heat quenching performed in the suitable segments on the part.
