Patent ID: 9181613
Filing Date: 2015-11-10
Classification: C23C,Y10T

Abstract:
1. A high tensile strength hot-dip galvannealed steel sheet having excellent coated-layer adhesiveness in which a hot-dip galvannealed layer is formed on the surface of a base steel sheet, wherein the base steel sheet contains Si by 0.04-2.5mass % and C by 0.06-0.15 mass %, and, when the surface roughness of the base steel sheet after the hot-dip galvannealed layer is removed by dissolution with an acid and is measured at a plurality of locations by a laser microscope, the arithmetic mean inclination angle (RΔa) is 23.0° or more and the root mean square inclination angle (RΔq) is 29.0° or more in 60% or more of all of the locations measured.