METHOD OF HOT CUTTING TREATMENT WITH GRINDING SURFACE LAYER GRAINS AND PRODUCT OBTAINED BY HOT CUTTING TREATMENT WITH CHANGE OF SURFACE LAYER GRAINS

摘要

Provided is a surface layer grain refining hot-shearing method including: heating and keeping a steel sheet in a temperature range of from Ac3 to 1400°C to austenitize the steel sheet; subsequently shearing the steel sheet in a state in which the steel sheet is placed on a die; and quenching by rapidly cooling the sheared steel sheet, wherein a start temperature of the shearing is set to be a temperature (°C) obtained by adding a temperature of from 30°C to 140°C to a previously measured Ar3 of the steel sheet.