Patent ID: 6911268

Claim:
A high strength hot-dip galvanized or galvannealed steel sheet having improved plating adhesion and press formability, said stool shoot comprising: (a) a steel sheet substrate comprising, by weight, carbon (C): 0.05 to 0.2%, silicon (Si); 0.2 to 2.0%, manganese (Mn): 0.2 to 2.5%, and aluminum (Al): 0.01 to 1.5%, said silicon and said aluminum having a mutual relationship represented by formula 0.4 (%)≦Si +0.8 Al (%)≦2.0%, said steel sheet substrate further comprising at least one member selected from the group consisting of (i) 0.003 to 1.0% of tin (Sn), (ii) 0.005 to 1.0% in total of at least one member selected from antimony (Sb), bismuth (Bi), and selenium (Se), (iii) 0.005 to 1.0% in total of at least one member selected from beryllium (Be), magnesium (Mg), calcium (Ca), and zirconium (Zr), and (iv) 0.005 to 1.0% in total of at least one member selected from scandium (Sc), yttrium (y), lanthanum (La), and cerium (Ce), with the balance consisting of iron (Fe) and unavoidable impurities, the volume fraction of retained austenite in the steel structure being 2 to 20%; and (b) a zinc (Zn) coated layer provided on said steel sheet substrate.