HIGH STRENGTH STEEL SHEET FOR HOT FORMING WITH EXCELLENT HEAT TREATMENT PROPERTY, HOT FORMED HARDENING MEMBER AND MANUFACTURING METHODS THEREOF

摘要

PURPOSE: A high strength steel plate and a hardening member for excellent heat treatability and a manufacturing method thereof are provided to increase to 100MPa or more of yield strength after plating. CONSTITUTION: A high strength steel plate for excellent heat treatability comprises C: 0.2~0.5 weight%, Si: 0.01~1.5 weight%, Mn: 0.5~2.0 weight%, P: less than 0.1 weight% (0% is exclusion), S: 0.03 weight% (0% is exclusion), available Al: less than 0.1 weight% (0% is exclusion), N: 0.01~0.1 weight%, Cr: 0.1~2.0 weight%, the rest Fe and the other impurity. Tension strength before heat forming is less than 800MPa.