To provide a carburizing furnace to implement a carburizing method in which the number of ethylene molecules in a carburizing chamber is substantially nonincreased from the beginning to the terminating period of carburization when ethylene and hydrogen are used as the vacuum carburizing gas.
The vacuum carburizing furnace comprises a carburizing chamber 2 to carburize a work inside, a vacuum carburizing gas feed means 4 to feed the vacuum carburizing gas containing ethylene gas and hydrogen gas to the work in the carburizing chamber 2 from the top, and an evacuating means 6 to suck the gas in the carburizing chamber 2 from the bottom of the work. It further comprises an increase/decrease detecting means 33 to detect the increase/decrease of the number of molecules of ethylene gas, and an exhaust quantity adjusting means 7 to adjust the exhaust quantity of the vacuum carburizing gas to be exhausted from the carburizing chamber 2 based on the increase/decrease of the number of molecules of ethylene gas.
KURATA HARUHIRO
MATSUBARA SHU
