| 摘要 |
PURPOSE: A method for manufacturing hot-rolled steel sheets for automobile wheel is provided, in which by adjusting the content of Mn and P, the weight ratio of Mn/S, the atomic ratio of B/N as well as conducting finish hot rolling at considerably low temperature ranges, hot-rolled steel sheets with excellent stretching workability is obtained. CONSTITUTION: The method includes the steps of reheating a steel slab comprising C 0.08-0.15 wt.%, Mn 0.3-0.8 wt.%, Si 0.2 wt.% or less, Al 0.03-0.10 wt.%, N 0.004-0.012 wt.%, P 0.02-0.08 wt.%, B 0.001-0.002 wt.%, S 0.02 wt.% or less, a balance of Fe and other inevitable impurities wherein the weight ratio of Mn/S is 40-60, the atomic ratio of B/N is 0.2-0.4; starting hot-rolling from the temperature range of 920 to 950°C; finish hot rolling in the temperature range of 730 to 780°C; and coiling the hot rolled steel sheet in the temperature range of 450 to 550°C. The hot-rolled steel sheet of the present invention has a carbide of 2.1 to 3.3μm in size and its strengthxductility value is higher than 1400 kgf/mm¬2·%.
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