| 摘要 |
<p>PURPOSE: A high-carbon hot rolled steel sheet, a cold rolled steel sheet, and a manufacturing method thereof are provided to secure uniform fine pearlite in a hot-rolling process by effectively controlling heat caused by phase transformation. CONSTITUTION: A method for manufacturing a high-carbon hot rolled steel sheet comprises a step of preparing high-carbon steel, a step of heating the steel and hot-rolling the steel in the austenite region to make a steel plate, wherein the finishing temperature of hot rolling in the austenite region is equal to or higher than Ar3 transformation temperature, a step of rapidly cooling the steel plate to 520-620°C in a ROT(Run-Out Table) before the beginning of phase transformation, a step of maintaining the cooling temperature so that the phase transformation of the cooled steel plate is implemented at one of the cooling temperatures, and a step of winding the steel plate at a cooling maintenance temperature.</p> |
