Patent ID: 8636852

Claim:
A galvanized steel sheet comprising, as an ingredient composition of the steel, C: more than 0.015% and lower than 0.100%, Si: 0.3% or lower, Mn: lower than 1.90%, P: 0.015% or more and 0.05% or lower, S: 0.03% or lower, sol.Al: 0.01% or more and 0.5% or lower, N: 0.005% or lower, Cr: lower than 0.30%, B: 0.0003% or more and 0.005% or lower, and Ti: lower than 0.014% in terms of mass %, satisfying 2.2≦[Mneq]≦3.1 and 0.42≦8[% P]+150B*≦0.73, comprising balance iron and inevitable impurities, comprising ferrite and a second phase as a microstructure of the steel, the second phase area ratio being 3 to 15%, the ratio of the area ratio of martensite and retained γ to the second phase area ratio being more than 70%, 50% or more of the area ratio of the second phase exists in the grain boundary triple point, [Mneq]=[% Mn]+1.3[% Cr]+8[% P]+150B* and B*=[% B]+[% Ti]/48×10.8×0.9+[% Al]/27×10.8×0.025 being established, [% Mn], [% Cr], [% P], [% B], [% Ti], and [% Al] represent the content of each of Mn, Cr, P, B, Ti, and sol.Al, respectively, and in the case of B*≧0.0022, B*=0.0022 being established.