| 摘要 |
PURPOSE: Provided is a step cooling method of high carbon wire rod for inhibiting the generation of martensite irrespective of the amount of segregation in central part of wire rod by controlling cooling rate according to temperature. CONSTITUTION: In a manufacture method of high carbon steel comprising C 0.4 to 0.9 wt.%, Si 0.01 to 1.0 wt.%, Mn 0.1 to 1.0 wt.%, 0.03 wt.% or less of P, 0.03 wt.% or less of S, Al 0.01 to 1.0 wt.%, a balance of Fe and incidental impurities, the method is characterized in that the high carbon wire rod steel undergoes hot rolling after heating at higher than 1000 deg.C; cold rolling at a cooling rate of 15 to 25 deg.C/sec over the temperature range of 900 to 550°C and at a cooling rate of 5 to 10 deg.C/sec over the temperature range of 550 to 300°C for improving elongation and reducing martensite.
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