| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method to directly soften a high carbon bearing steel after the hot rolling or the hot forging. SOLUTION: In an inline softening heat treatment method, a hot rolled wire and a hot forged parts are primarily cooled to 500-250 deg.C while the cooling speed at 800-500 deg.C is adjusted to 0.5-5 deg.C/second, and then, re-heated to 780-880 deg.C in a short time, and kept at the temperature for the time not exceeding the time expressed by the formula t=530-0.6×T (where, t is the keeping time (second), and T is the re-heating temperature ( deg.C)), and secondarily cooled to 600 deg.C at the cooling speed of 0.1 to 3 deg.C/second.
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