| 摘要 |
An annular workpiece quenching method includes: cooling an annular workpiece (W) with an inner die (23) arranged radially inward of the workpiece heated at a quenching temperature; pressing the workpiece in a width direction at a low pressure and inserting the workpiece in an outer die (22) with restraint of an inner peripheral surface of the workpiece continued, when the restraint is started by contact with the inner die, after a temperature of the workpiece is decreased to 500°C or lower but before the temperature is decreased to a martensitic transformation start temperature (Ms point); and restraining the workpiece in the width direction by pressing the workpiece in the width direction at a high pressure, and restraining an outer peripheral surface of the workpiece that undergoes volume expansion due to martensitic transformation, using the outer die, after the temperature of the workpiece is decreased to the Ms point or lower. |
