| 摘要 |
<p>PURPOSE:To provide the method for heat-treating steel capable of holding the hardness of the steel after being subjected to tempering into a prescribed value while the heat treating time in the tempering is reduced and capable of preventing the martensitization of the structure at the time of cooling. CONSTITUTION:At the time of tempering steel, in the temp. rising process, the steel is heated with a high high-frequency output, and in the case where it approaches the heat treating temp., the high-frequency output is reduced a little, and its overshoot can be prevented. Next, the high-frequency output is weakened, and the steel is held under soaking and is thereafter gradually cooled. By this treatment, its heating properties can easily be put into the optimum heat treating area, the hardness of the steel after being subjected to the tempering treatment can be regulated to a prescribed standard value and the martensitization of the structure at the time of the cooling can be prevented.</p> |
