| 摘要 |
Disclosed are a steel product and a manufacturing method thereof, wherein the steel product can have not only a tensile strength of at least 1470 MPa but also a retainable galvanized layer after hot-stamping. The manufacturing method of the steel product according to the present invention comprises: a step (a) of preparing a blank from a steel sheet; a step (b) of heating the blank; and a step (c) of cooling the heated blank to at most the Ms temperature of the steel sheet after hot-pressing the steel sheet. The steel sheet having zinc in the surface thereof comprises 0.2 to 0.4 wt% of C, 0.02 to 0.4 wt% of Si, 1.0 to 4.0 wt% of Mn, at most 0.2 wt% of P, at most 0.1 wt% of S, 0.2 to 1.0 wt% of Cr, 0.01 to 0.1 wt% of Al, 0.02 to 0.2 wt% of Ti, 0.002 to 0.005 wt% of B, and remnants Fe and inevitable impurities; further includes at least one kind of at most 2.0 wt% of Ni and at most 1.5 wt% of V; and satisfies a formula of [Ni]+[V] >= 0.03 (symbol [] represents wt% corresponding to each element). [Reference numerals] (AA) Start; (BB) End; (S110) Prepare a blank; (S120) Heat the blank; (S130) Apply hot press forming/cooling |
