Abstract: A high-strength galvanized steel sheet is provided which has a tensile strength of a level of about 590 MPa and superior formability, including a coating with good appearance. The galvanized steel sheet includes a base steel and a galvanized coating layer formed over the surface of the base steel. The galvanized steel sheet has a chemical composition containing 0.005% to 0.12% of C, 0.7% to 2.7% of Si, 0.5% to 2.8% of Mn, 0.1% or less of P, 0.07% or less of S, 1.0% or less of Al, 0.008% or less of N, and the balance being Fe and inevitable impurities on a mass basis, and a microstructure constituted of at least 90% of ferrite and 2% to 10% of martensite on an area basis. The ferrite has a Vickers hardness of 120 or more on average, and an inclusion is precipitated from the grain boundary with a length of 50% or less relative to the entire length of the grain boundary in the surface layer of the base steel with a depth of 3 ?m from the interface between the coating layer and the base steel.

Abstract: The hot-dip galvanized steel sheet has: a steel sheet containing 0.1 to 3.0% of Si by mass; a hot-dip galvanizing layer; and a segregated layer, being placed between the steel sheet and the hot-dip galvanizing layer, having a thickness in a range from 0.01 to 100 ?m; containing an oxide containing Si, and being composed of at least one component selected from the group consisting of S, C, Cl, Na, K, B, P, F, and N. The hot-dip galvanized steel sheet shows beautiful surface appearance without generating non-plating portion and provides excellent plating adhesion and sliding property in spite of using a base steel sheet containing a large quantity of Si. Furthermore, the alloy hot-dip galvanized steel sheet obtained by allying the hot-dip galvanized plating also has excellent anti-powdering property.