Dowa Mining Co., Ltd.

Dowa Thermotech Co., Ltd.

Hidetoshi Juryozawa

Jun Takahashi

Fumitaka Abukawa

Hisashi Ebihara

Keiji Yokose

The invention provides a carburization treatment method in which the carburization treatment is conducted under a condition where an atmosphere within the furnace is maintained at a high carbon potential which is slightly blow a carbon solid solubility. Preferably, the internal pressure within the furnace is kept at 0.1 to 101 kPa, the hydrocarbon gas is one, two or more than two kinds of gases selected from the group consisting of CH, CH, CH, CH, CH, CHand CH, while the oxidative gas is an air, an Ogas, or COgas.

Carburization treatment method

The invention provides a carburization treatment method in which a carburization treatment is conducted simultaneously with an operation of supplying a hydrocarbon gas and an oxidative gas into a furnace kept under a reduced pressure. Preferably, the internal pressure within the furnace is kept at 0.1 to 101 kPa, the hydrocarbon gas is one, two or more than two kinds of gases selected from the group consisting of CH, CH, CH, CH, CH, CHand CH, while the oxidative gas is an air, an Ogas, or COgas.

Carburization treatment method and carburization treatment apparatus

A vacuum heat treatment furnace comprising a furnace shell, a casing arranged in an inner side of the furnace shell, a heat insulating layer consisting of a thick plate-like alumina-silica series ceramic fiber blanket and a thin plate-like alumina series ceramic material arranged in an inside of the casing, and a heater arranged in a heating room surrounded by the heat insulating layer. A method of and apparatus for measuring a carbon concentration in an atmosphere in a treating room having a reduced pressure, wherein a carbon concentration measuring body is transferred from an external portion of a furnace shell of a heat treatment furnace into the treating room within the furnace shell, the carbon concentration measuring body is reacted with the atmosphere in the treating room for a predetermined time, the carbon concentration measuring body is gradually cooled for a predetermined time, and an amount of carbon in the carbon concentration measuring body is measured in atmospheric pressure at room temperature.

Vacuum heat treatment furnace and method of and apparatus for measuring carbon concentration in atmosphere having reduced pressure.

A vacuum heat treatment furnace comprising a furnace shell, a casing arranged in an inner side of the furnace shell, a heat insulating layer consisting of a thick plate-like alumina-silica series ceramic fiber blanket and a thin plate-like alumina series ceramic material arranged in an inside of the casing, and a heater arranged in a heating room surrounded by the heat insulating layer. A method of and apparatus for measuring a carbon concentration in an atmosphere in a treating room having a reduced pressure, wherein a carbon concentration measuring body is transferred from an external portion of a furnace shell of a heat treatment furnace into the treating room within the furnace shell, the carbon concentration measuring body is reacted with the atmosphere in the treating room for a predetermined time, the carbon concentration measuring body is gradually cooled for a predetermined time, and an amount of carbon in the carbon concentration measuring body is measured in the atmospheric pressure at a room temperature.

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Tokyo, Japan

Hidetoshi Juryozawa