| 摘要 |
PURPOSE:To control the atmosphere in a heat treatment furnace to an adequate state in a short period by adjusting the atmosphere components in the heat treatment furnace by the feed rates of a carrier gas, enriching gas and reducing gas at the time of subjecting a metallic material to an atmosphere heat treatment. CONSTITUTION:An inexpensive org. liquid such as methanol or the thermal cracking gas thereof is supplied as the carrier gas into the heat treatment furnace in the case of subjecting the member consisting of a ferrous or nonferrous metal to a carburization hardening treatment to improve the wear resistance and resistance to fatigue of the surface thereof. The enriching gas such as methane, propane or butane or the reducing gas such as CO2 or air is fed to the heat treatment furnace according to the analysis value of the atmosphere gas in order to adequately control the carbon concn. in the atmospheric gas of said furnace, by which the carbon concn. of the atmospheric gas in the heat treatment furnace is quickly and adequately controlled to the prescribed value. The surface treatment to provide the extremely good hardness distribution by the hardening treatment of the uniform carburization concn. is executed.
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