| 摘要 |
PROBLEM TO BE SOLVED: To realize a gas carburization (carbonitriding) method where the formation of an intergranular oxidized layer on the surface of a steel member can be prevented, a carburizing reaction can be made easy to progress, and sooting is less liable to occur as well. SOLUTION: As a treatment furnace, a vacuum furnace having high airtightness is used. As carburizing gas, no enriched gas is used but only carrier gas. In the case the steel member is subjected to carburization (carbonitriding) treatment, prior to the feed of the carrier gas into the vacuum furnace, the pressure in the vacuum furnace is reduced, by which the concentration of oxygen in the vacuum furnace is made extremely small. Thereafter, the temperature in the vacuum furnace is raised, the pressure in the vacuum furnace is restored, and thereafter the steel member is subjected to a carburization (carbonitriding) treatment. COPYRIGHT: (C)2005,JPO&NCIPI
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