Dowa Mining Co., Ltd.

Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Dowa Thermotech Co., Ltd.

Tokyo Heat Treating Company, Ltd.

Fumitaka Abukawa

Jun Takahashi

Keiji Yokose

Hisashi Ebihara

Hidetoshi Juryozawa

Hitoshi Goi

Hideki Inoue

Masahiko Watanabe

Hiroshi Shimura

Hirofumi Kamisugi

Toshiyuki Kawamura

Kazuyoshi Fujita

Shinichi Takemoto

Tadayoshi Juge

Hidetoshi Juryosawa

Shin Kurasawa

Nobuo Nishioka

Yoshiaki Shimizu

Keishichi Namba

Yuichi Takasu

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.

Vacuum heat treatment furnace

Method and apparatus for carburizing, quenching and tempering workpieces, by which the step of carburizing can be incorporated into a machining and manufacturing process to be performed by an on-line machining and manufacturing system as one stage thereof, and by which high-quality treatment or processing can be achieved without occurrences of variation in quality among heat-treated products. In this apparatus, a preheating chamber (2), six carburizing chambers (5a to 5f), a cooling chamber (6), a reheating chamber (7), a quenching chamber (8) are placed around an intermediate chamber (4) having a transport device (12). Further, a high-frequency induction heating technique is used for heating each of major ones of the treatment or processing chambers. Moreover, a plasma carburizing method is performed in the carburizing chambers. Furthermore, workpieces, which are successively carried into this apparatus through a machining and manufacturing line, are assigned and distributed to the chambers, respectively, and are then treated or processed therein. Thus, the process of carburizing, quenching and tempering can be performed without stagnation.

Method and apparatus for carburizing, quenching and tempering

In a method for quenching metal parts, a quenching chamber is provided in which the quenching oil is continuously supplied from below the steel parts and circulated upward through the parts in a laminar flow. The circulation is accomplished by feeding the quenching oil onto the bottom of the quenching chamber of an auxiliary chamber surrounding it.

Apparatus for steel hardening and process therefor

In a cementation method of metals in which hydrocarbon gas and oxidization gas are introduced into a heat treatment furnace, a small quantity of hydrocarbon gas of is introduced at a low pressure into the heat treatment furnace. The shift time and the gradient of the carbon potential varying toward a predetermined high or low level are controlled by increasing or decreasing the quantity of cementation gas and oxidization gas to be supplied to the furnace. After the carbon potential is reached to the high or low level, the carbon potential is maintained for a predetermined time period so as to prevent the deposited carbide from being bulked. In order to prevent the gas supply pipe from being choked with the soot of the hydrocarbon, oxidization gas of intermediate pressure is flushed into the gas supply pipe. In order to prevent the components of the atmosphere in the furnace from varying due to the change in furnace pressure when the door is opened or closed, hydrocarbon gas of a low pressure and oxidization gas of an intermediate pressure are added in the conversion pipe in the preheating zone. CO.sub.2 of intermediate pressure is supplied into each gas supply pipe at the same time in order to remove the soot in each of the gas supply pipes and to prevent the lack of CO to be introduced into the furnace.

Cementation method of metals

Gas carburizing method and apparatus

Growing community of inventors

Tokyo, Japan

Fumitaka Abukawa