| 摘要 |
PROBLEM TO BE SOLVED: To provide a quenching method of causing little distortion by gas cooling. SOLUTION: This quenching method comprises: a first step of cooling an article to be treated which is held at a predetermined quenching temperature, to a temperature which is in the vicinity of and higher than the martensitic-transformation-starting temperature, by circulating a coolant gas of a high pressure; a second step of holding the article having passed through the first step at a temperature which is in the vicinity of and higher than the martensitic-transformation-starting temperature, by decreasing a cooling rate for the article; and a third step of cooling the article having passed through the second step to a lower temperature than the martensitic-transformation-starting temperature. COPYRIGHT: (C)2005,JPO&NCIPI
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