| 摘要 |
PURPOSE: A hot-rolled steel sheet with excellent surface properties and formability and a manufacturing method thereof are provided to short-blast short balls with a size of 0.1-0.4 mm on the surface of the hot-rolled steel sheet at 40-65 m/sec. CONSTITUTION: A manufacturing method of a hot-rolled steel sheet with excellent surface properties and formability is as follows. Short balls with a size of 0.1-0.04 mm are short-blasted on the surface of the hot-rolled sheet at 40-65 m/sec. The hot-rolled steel sheet is made of steel composed of 0.01-0.10 wt.% of C, 0.5-1.5 wt.% of Mn, 0.01-0.06 wt.% of P, 0.020 wt.% or less of S(not including 0 wt.%), 0.01-0.07 wt.% of Al, 0.001-0.004 wt.% of N, 0.02-0.06 wt.% of Ti, 0.01-0.05 wt.% of Co, and the rest of Fe and other inevitable impurities. The component of the steel satisfies 0.015<=[(Ti×Co) / C]weight ratio <=0.06. [Reference numerals] (a) Normal ferrite rib; (b) Transformed ferrite rib |
