| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum carburizing method which uses a pretreatment chamber capable of efficiently utilizing a raw material and reducing energy loss. SOLUTION: In the vacuum carburizing method, a predecomposed gas generated under controlled pressure and temperature in the pretreatment chamber is supplied to a vacuum carburizing apparatus wherein a work is placed and subjected to vacuum carburizing. A saturated hydrocarbon gas, e.g. methane, ethane, propane, or butane, is supplied to the pretreatment chamber and treated while the temperature in the chamber is controlled so as to generate an ethylene gas in a large amount. The resultant unsaturated hydrocarbon gas is supplied from the chamber to the carburizing apparatus. In the chamber, the treatment is conducted at 600°C or higher but lower than 1,000°C; preferably, a propane gas is treated at 700°C or higher but lower than 800°C. COPYRIGHT: (C)2004,JPO
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