| 摘要 |
PROBLEM TO BE SOLVED: To provide a hot press member having excellent ductility which has TS of 1,300 to 1,450 MPa and El of about 10.0 to 14%; to provide a steel sheet for the hot press member; and to provide a method for producing the hot press member. SOLUTION: The hot press member having excellent ductility has a composition containing, by mass, 0.18 to 0.21% C, 0.05 to 2.0% Si, 0.5 to 3.0% Mn,≤0.05% P,≤0.05% S, 0.005 to 0.1% Al and≤0.01% N, and the balance Fe with inevitable impurities, and has a microstructure where the area ratio of a martensitic phase occupied in the whole structure is 90 to 100%, and also, the average grain size of old austenitic grains is≤8μm. COPYRIGHT: (C)2010,JPO&INPIT |
