| 摘要 |
PURPOSE: Provided is an ultra high strength steel panel for road wheel rim of automobile by adding a certain amount of both Ti and Nb for the purpose of precipitating TiC and NbC in matrix. The ultra high strength steel panel exhibits a tensile strength of greater than 80 Kgf/mm¬2 and a yield strength of greater than 65 Kgf/mm¬2. CONSTITUTION: The method for manufacturing ultra high strength steel panel includes the steps of continuous casting a steel comprising C 0.09 to 0.11 wt.%, Si 0.025 to 0.049 wt.%, Mn 1.70 to 1.85 wt.%, Ti 0.12 to 0.15 wt.%, Nb 0.040 to 0.050 wt.%, P 0.010 to 0.015 wt.%, Al 0.020 to 0.035 wt.%, S 0.001 to 0.002 wt.%, a balance of Fe and incidental impurities; hot rolling the steel sheet at 1,100 to 1,300 deg.C; and coiling it at 600 to 900 deg.C.
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