| 摘要 |
Provided are: a high-strength hot-dip zinc-coated steel sheet which has tensile strength (TS) of 780 MPa or more and is therefore highly strong, and also has excellent bendability, fatigue properties and surface appearance; and a method for producing the high-strength hot-dip zinc-coated steel sheet. The high-strength hot-dip zinc-coated steel sheet contains 0.05 to 0.15% inclusive of C, 0.01 to 1.00% inclusive of Si and 2.2 to 3.5% inclusive of Mn and additionally contains 0.01 to 0.10% inclusive of Nb and/or 0.01 to 0.10% inclusive of Ti. In the steel sheet, 5 to 80% by area inclusive of a ferrite phase, 20 to 70% by area inclusive of a martensite phase and 0 to 25% by area inclusive of a bainite phase are present on a face which is located at a half depth of the steel sheet as observed in the thickness direction, the hardness on a face which is located at a depth of 5 μm as observed in the thickness direction from the surface layer of the steel sheet is 80% or less relative to the hardness on the face which is located at a half depth of the steel sheet as observed in the thickness direction, and the hardness on a face which is located at a depth of 15 μm as observed in the thickness direction from the surface layer of the steel sheet is 90% or more relative to the hardness on the face which is located at a half depth of the steel sheet as observed in the thickness direction. |
