Mitsubishi Jukogyo Kabushiki Kaisha

Nisshin Steel Co., Ltd.

Mitsuo Katoh

Kenichi Yanagi

Toshiharu Kittaka

Yoshio Shimozato

Tetsuyoshi Wada

Kanji Wake

Norio Tsukiji

Takuya Aiko

Heizaburo Furukawa

Yasuji Nakanishi

For vacuum deposition plating steel strip, a vacuum deposition plating apparatus is used including an inlet-side vacuum sealing device provided in front of a vacuum deposition plating chamber, with an inlet-side inactive gas replacement chamber provided between the inlet-side vacuum sealing device and an annealing furnace. An outlet-side vacuum sealing device is provided at the rear of the vacuum deposition plating chamber, with an outlet-side inactive gas replacement chamber provided between the outlet-side vacuum sealing device and the atmosphere. An inactive gas circulating/purifying device circulates an inactive gas from vacuum chambers of both the vacuum sealing devices to atmospheric pressure chambers of both the vacuum sealing devices and removes water, oil and oxygen from the inactive gas. Oxygen and hydrogen in the inactive gas are regulated to provide 60 ppm or less of oxygen and 0.2 to 2.0% of hydrogen, and also to regulate the dew point of the inactive gas to -50.degree. C. or less. Further, a pressure P.sub.1 in the annealing furnace, a pressure P.sub.2 in the inlet-side inactive gas replacement chamber, and a pressure P.sub.3 in the outlet-side inactive gas replacement chamber are maintained at atmospheric pressure or more. A value of P.sub.1 -P.sub.2 can be kept at 0 mmAq or more, and the concentration of hydrogen in the inlet-side inactive gas replacement chamber is held to 2.0.degree. or less.

Method for vacuum deposition plating steel strip

A vacuum deposition plating apparatus having an inlet-side vacuum sealing device provided in front of a vacuum deposition plating chamber, an inlet-side inactive gas replacement chamber provided between the inlet-side vacuum sealing device and an annealing furnace, an outlet-side vacuum sealing device provided in the rear of the vacuum deposition plating chamber, an outlet-side inactive gas replacement chamber provided between the outlet-side vacuum sealing device and the atmosphere, and an inactive gas circulating/purifying device for circulating an inactive gas from vacuum chambers of both the vacuum sealing devices to atmospheric pressure chambers of both the vacuum sealing devices and for removing water, oil and oxygen from the inactive gas; a pressure gauge provided on the annealing furnace; a pressure gauge, a control valve, an automatic valve, a hydrogen concentration detector and a discharge valve provided on the inlet-side inactive gas replacement chamber; a pressure gauge and an automatic valve provided on the outlet-side inactive gas replacement chamber; and an automatic valve connecting to an inactive gas tank for emergency provided on the atmospheric pressure chambers of both the vacuum sealing devices.

Method and apparatus for vacuum deposition plating

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Hiroshima, Japan

Mitsuo Katoh