| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-tension hot-dip galvanized steel sheet free from generation of unplated spots. SOLUTION: A substrate steel sheet of this high-tension hot-dip galvanized steel sheet includes 0.1 mass% or less C, 0.3-2.0 mass% Si, and 1.0-3.0 mass% Mn, 0.01-0.5 mass% one or more selected from Nb, Ti, V, and Zr, and the balance Fe with unavoidable impurities, has a structure in a central part of sheet thickness, which is a composite structure consisting of a ferrite phase and at least one phase among a martensitic phase, a bainite phase, and a retained austenite phase, has a structure in the surface layer part in a range of 30μm or shallower from the surface of the substrate steel sheet, which consists of the ferrite phase occupying 90% or more by an area rate, and has an average crystal particle diameter of the above ferrite phase of 3.5μm or less. |
