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Title:
QUALITY CONTROL METHOD IN VACUUM CARBURIZING AND VACUUM CARBURIZING FURNACE
Document Type and Number:
Japanese Patent JP2007113045
Kind Code:
A
Abstract:

To provide a quality control method in vacuum carburizing where the judgement of the degree in the variation of carburizing quality is facilitated, and the control of the carburizing quality can be easily performed, to provide a vacuum carburizing furnace therefor, and further, to provide a vacuum carburizing furnace where the reproducibility of carburizing quality is improved, the variation in the carburizing quality is reduced, and its uniformity can be secured.

In accordance with the carburizing depth and surface carbon concentration required for a work, based on the diffusion of carbon into the work, the time change of the theoretical flow rate of the carburizing gas required for carburizing treatment is found, based on the time change of the theoretical flow rate, the partial pressure ratio of hydrogen produced by carburizing reaction in the theoretical flow rate to the whole pressure in a treating chamber is regarded as a theoretical hydrogen partial pressure ratio, the time change of the theoretical hydrogen partial pressure ratio is found, the time change of the theoretical hydrogen partial pressure ratio and the time change of the hydrogen partial pressure ratio to the whole pressure in the treating chamber upon actual carburizing treatment are compared, and, based on their approximate degree, the degree of the variation in the carburizing quality in the same operation batch is judged.


Inventors:
NAKABAYASHI TAKASHI
TAKAHASHI JINICHIRO
ISHIGE KENGO
SHIGEGAKI YASUHIRO
Application Number:
JP2005304250A
Publication Date:
May 10, 2007
Filing Date:
October 19, 2005
Export Citation:
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Assignee:
ISHIKAWAJIMA HARIMA HEAVY IND
International Classes:
C23C8/20; C21D1/06; C21D1/76; C21D1/773; F27B5/04
Domestic Patent References:
JP2002173759A2002-06-21
JP2004332075A2004-11-25
JPH04107256A1992-04-08
Attorney, Agent or Firm:
Minoru Hotta
Yasuharu Nakasone
Toshihiro Nomura