Patent ID: 8388771
Filing Date: 2013-03-05
Classification: B32B,C21D,C22C,Y10T

Abstract:
1. A high strength steel sheet comprising, in percent by mass: C: 0.03 to 0.2%; Si: 0.6 to 2.5%; Mn: 1 to 3.0%; Cr: 0.01 to 0.5%; Mo: 0.01 to 0.5%; Al: 0.02 to 0.15%; Ti: 0.15% or less; Nb: 0.15% or less; and V: 0.15% or less, wherein a metal structure of the steel sheet includes a mixed structure of ferrite and a second phase, a fraction of ferrite is 10% to 80%, and a fraction of the second phase is 20% to 90%; the content of Si satisfies formula (1), provided, α=6.9×([C]+[Mn]/6+[Cr]/5+[Mo]/4+[Ti]/15+[Nb]/17+[V]/14) 1/2 is given, wherein [ ] shows the quantity (mass percent) of each element contained in the steel sheet; an area ratio (S the steel sheet satisfies TS×El is 17000 MPa % or more, wherein TS represents tensile strength of the steel sheet in MPa and El represents elongation percentage of the steel sheet in %.