| 摘要 |
PROBLEM TO BE SOLVED: To provide a quenching method, with which the strain caused by rapid cooling and martensite transformation can be restrained. SOLUTION: In a low strain quenching method, with which a member to be quenched, disposed in the inner part of a quenching furnace is quenched by rapidly cooling from the higher temp. than the transformation point with gas for cooling, at the point of time becoming the higher temp. than the martensite transformation point after the cooling starts, at least one side of the flow rate of the cooling gas and the pressure of the cooling gas in the quenching furnace, is temporarily lowered. As the other way, when the member is cooled as the above method, the surroundings, in which the member to be cooled is disposed, are temporarily heated.
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