| 摘要 |
<p>A method for quenching a mold, comprising: a heating/retention step of heating the mold and retaining the mold at a temperature which is equal to or higher than an A3 transformation point and lower than 1150°C; a first cooling step of, subsequent to the heating/retention step, immersing the mold in an oil vessel to cool the mold by oil cooling until the surface of the mold has a temperature which is equal to or lower than 700°C and higher than an Ms point; an improved retention step of, subsequent to the first cooling step, pulling the mold out of the oil vessel to interrupt the oil cooling and retaining the mold until the surface of the mold has a temperature which is higher than the Ms point and at which the difference between the temperature of the surface of the mold and the temperature of the inside of the mold falls within 200°C; and a second cooling step of, subsequent to the improved retention step, cooling the mold at a cooling rate of 1-50°C/min until the surface of the mold has a temperature of 200°C.</p> |
