Nippon Kokan Kabushiki Kaisha

Akio Shiwata

Teruyuki Hasegawa

Tsuneo Kondo

Yoshimi Komatsu

Hirohisa Nakashima

Ryuji Yamaguchi

Seigo Kuwano

Kazuhiko Matsuo

Yasuhiro Matsuda

Yusuke Shirotani

Yoneichi Hamada

The gap between an insertion hole formed in a covering of a ladle and an electrode inserted through the insertion hole is sealed by sealing means. The sealing means has a cap seal longitudinally and slidably fitted over the electrode. A base seal is hermetically disposed between the cap seal and the covering in such a manner that a gap is provided between the electrode and the base seal. The base seal has a gas injection nozzle intended to discharge a gas toward the electrode and another gas injection nozzle intended to discharge the gas downwardly. The use of the base and cap seals enables securing the sealing functions thereof despite any movement of the electrode, thus preventing the pickup of [N] as well as the reoxidation of molten steel. When a gas seal is effected by the formation of a flow of gas rotating around the electrode about the axis thereof, the sealing performance can be more enhanced. Further, when the base seal is cooled by causing cooling water to be circulated therethrough, its durability can also be enhanced.

Arc-heating type extra-furnace refining apparatus

Growing community of inventors

Fukuyama, Japan

Akio Shiwata