MANUFACTURING METHOD OF PRESS BAKE TOOL FOR HIGH STRENGH AND HIGH TOUGHNESS WITH 100KGF/' YIELD STRENGTH

摘要

A manufacturing method of a high strength and high toughness bending mold is provided to secure internal force and internal toughness, minimize treatment deformation, and secure an internal force of 100 kgf/mm^2 by subjecting a steel product for carburization to carburization heat treatment, thereby hardening the surface of the steel product. A manufacturing method of a high strength and high toughness bending mold with an internal force of 100 kgf/mm^2 comprises: a step of preparing a steel product for a bending mold; a step of performing carburization diffusion of the steel product in a carburizing atmosphere of 900 to 1,000 deg.C; a step of performing oil quenching of the carburization diffused steel product in a temperature range of 800 to 850 deg.C at a temperature of 60 to 80 deg.C; and a step of performing low temperature tempering of the oil quenched steel product at 150 to 200 deg.C. The manufacturing method further comprises: a step of tempering the oil quenched steel product at 120 deg.C after performing the oil quenching step; and a step of subzero treating the steel product temperature at 120 deg.C in a temperature range of -70 to -90 deg.C.