| 摘要 |
PURPOSE: A method for manufacturing a high carbon steel strip is provided which has superior ductility and quenching heat-treatment by adjusting graphitization promoting elements, graphitization restraining elements, B, N and Ti and appropriately controlling hot rolling conditions and annealing heat-treatment conditions. CONSTITUTION: The method comprises the processes of manufacturing a hot rolled steel sheet by hot rolling a steel product comprising 0.3 to 0.8 wt.% of C, 0.1 to 1.5 wt.% of Si, 0.1 to 0.5 wt.% of Mn, 0.01 to 0.1 wt.% of Al, 0.00065 to 0.0026 wt.% of N, (0.0005+0.77N)≤B()≤(0.003+0.77N) and a balance of Fe and impurities at a finishing rolling temperature of 900 deg.C or less and a coiling temperature of 650 deg.C or less; and making ferrite and graphite main substances by annealing the manufactured hot rolled steel sheet at a temperature ranging from 650 to 710 deg.C. The method comprises the processes of manufacturing a hot rolled steel sheet by hot rolling a steel product comprising 0.3 to 0.8 wt.% of C, 0.1 to 1.5 wt.% of Si, 0.1 to 0.5 wt.% of Mn, 0.01 to 0.1 wt.% of Al, 0.0026 to 0.015 wt.% of N, (N-0.0026)/0.29≤Ti()≤ (N-0.00065)/0.29, 0.0005+0.77(N-0.29Ti)≤B()≤0.003+0.77(N-0.29Ti) and a balance of Fe and impurities at a finishing rolling temperature of 900 deg.C or less and a coiling temperature of 650 deg.C or less; and making ferrite and graphite main substances by annealing the manufactured hot rolled steel sheet at a temperature ranging from 650 to 710 deg.C.
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