| abstract |
(57) [Summary] [PROBLEMS] The present invention devises the base material of a steel sheet to “unplate” during hot-dip plating, “unevenness in alloying” during alloying treatment after plating, and It is an object of the present invention to provide a high-strength hot-rolled steel sheet that does not cause “cissing” or “unevenness” during processing or chromate processing. SOLUTION: C: 0.001 to 0.30 wt%, S i: 0.001 to 3.0 wt%, Mn: 0.1 to 3.0 wt%, Cr: 0.001 to 2.0 wt%, with the balance of iron and unavoidable impurities, in the grain boundaries and / or in the crystal grains of the surface layer of the steel plate, plating properties, alloying processability after plating. A high-strength hot-rolled steel sheet comprising an oxide effective for improving chemical conversion and chromate treatment properties. |