To provide a method for controlling quality of vacuum carburization and a vacuum carburizing furnace enabling easy control of carburization quality by facilitating determination of the degree of variation in the carburization quality, the vacuum carburizing furnace being capable of improving reproducibility of the carburization quality and of reducing the variation in the carburization quality, thereby assuring the quality uniformity.
Depending on a carburized depth and a surface carbon concentration required for a workpiece, a time change of the theoretical flow rate of carburizing gas required for carburizing treatment is calculated based on diffusion of carbon into the workpiece. Assuming a partial pressure ratio or hydrogen produced by the carburizing reaction at the theoretical flow rate to the total pressure in the process chamber as a theoretical hydrogen partial pressure ratio, the time change of the theoretical hydrogen partial pressure ratio is calculated based on the time change of the theoretical flow rate. The time change of the theoretical hydrogen partial pressure ratio and the time change of the hydrogen partial pressure ratio to the total pressure in the process chamber during an actual carburizing treatment are compared, and the degree of the variation in the carburization quality in the same operation batch is determined based on the approximation degree.
TAKAHASHI JINICHIRO
ISHIGE KENGO
SHIGEGAKI YASUHIRO
| JPS5896866A | 1983-06-09 | |||
| JPS5315232A | 1978-02-10 | |||
| JPS5952705B2 | 1984-12-21 | |||
| JPS5428378B2 | 1979-09-17 | |||
| JP2002173759A | 2002-06-21 | |||
| JP2004332075A | 2004-11-25 | |||
| JP2007113045A | 2007-05-10 | |||
| JPS5896866A | 1983-06-09 | |||
| JPS5315232A | 1978-02-10 | |||
| JPS5952705B2 | 1984-12-21 | |||
| JPS5428378B2 | 1979-09-17 | |||
| JP2002173759A | 2002-06-21 | |||
| JP2004332075A | 2004-11-25 |
Toshihiro Nomura
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