| 摘要 |
This base steel sheet has a hot-dip galvanized layer formed on the surface, and the volume fraction of a retained austenite phase of the steel sheet structure in a range of 1/8 of the sheet thickness to 3/8 of the sheet thickness, centered around 1/4 of the sheet thickness, from the surface, is not more than 5%, and the total volume fraction of a bainite phase, a bainitic ferrite phase, a fresh martensite phase, and a tempered martensite phase is not less than 40%. The average effective grain size is not more than 5.0 μm, and the maximum effective grain size is not more than 20 μm. A decarburized layer with a thickness of 0.01 to 10.0 μm is formed on a surface section, the density of oxides, which are dispersed in the decarburized layer is 1.0 × 1012 to 1.0 × 1016 oxides/m2, and the average particle size of the oxides is not more than 500 nm. |
