| 摘要 |
This invention provides a high strength galvanized steel sheet having a low YP, a high BH, excellent anti-aging properties, and excellent corrosion resistance without requiring the addition of a large amount of expensive elements, such as Mo or Cr, or a special CGL heat history and a method for manufacturing the same. The high strength galvanized steel sheet contains 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%, and satisfies 2.2 <= [Mneq] <= 3.1 and 0.42 <= 8[%P] + 150B* <= 0.73. The steel microstructure contains ferrite and a second phase, in which the second phase area ratio is 3 to 15%, the ratio of the area ratio of martensite and retained .gamma. to the second phase area ratio is more than 70%, and 50% or more of the area ratio of the second phase exists in the grain boundary triple point. |
