Nkk Corporation

Jp Steel Plantech Co.

Norio Ao

Toshimichi Maki

Ryuji Yamaguchi

Hirotsugu Kubo

Hideaki Mizukami

Mikio Suzuki

Kazuhiko Mori

Akio Nagamune

Takashi Nakayama

Yasuhiro Sato

Yoshiyuki Kanao

Hironori Yamamoto

Teruo Tatefuku

Shinobu Miyahara

Toru Kitagawa

Akihiko Morita

Akio Nishino

The present invention provides an arc-melting apparatus which attains extremely high efficiency by preheating scraps using exhaust gas from the melting chamber. The arc-melting apparatus needs for no device to carry and supply an iron source to a melting chamber, which makes it possible to preheat the next charge. The arc-melting apparatus has a melting furnace which melts scraps, a preheating shaft connected directly to an upper part of one side of the melting furnace, an arc electrode for melting scraps in the melting furnace, a bucket for supplying scraps to the preheat shaft so as to continuously maintain scraps in the melting furnace and in the preheating shaft, a tapping portion having a tapping hole, being projected outward from the melting furnace and a tilting device for tilting the melting furnace on a side of the tapping portion. The tapping portion is arranged at an orthogonal direction to the direction of the supplied cold iron source. The preheating shaft of the melting furnace and the tapping portion have a distance between the mutual part, so that scraps do not flow out on a the tapping hole side.

Apparatus for arc-melting cold iron source and method thereof

The present invention provides an arc-melting apparatus, which attains extremely high efficiency by preheating scraps using exhaust gas from the melting chamber. The arc-melting apparatus needs for no device to carry and supply an iron source to a melting chamber, which makes it possible to preheat the next charge. The arc-melting apparatus has a melting furnace which melts scraps, a preheating shaft connected directly to an upper part of one side of the melting furnace, an arc electrode for melting scraps in the melting furnace, a bucket for supplying scraps to the preheat shaft so as to continuously maintain scraps in the melting furnace and in the preheating shaft, a tapping portion having a tapping hole, being projected outward from the melting furnace and a tilting device for tilting the melting furnace on a side of the tapping portion. The tapping portion is arranged at an orthogonal direction to the direction of the supplied cold iron source. The preheating shaft of the melting furnace and the tapping portion have a distance between the mutual part, so that scraps do not flow out on a the tapping hole side.

A melting furnace including preheating vessels for preheating raw material, and a melting furnace body having a tilting device and a heating device for heating the preheated raw material. A furnace roof covers an upper part of the melting furnace body and a combustion chamber for burning a gas generated in the melting furnace body is arranged on the furnace roof. Feed openings are arranged at side faces of the combustion chamber to feed the preheated raw material into the melting furnace body, and the side faces of the combustion chamber are positioned at a right angle to a tilting direction of the melting furnace body. Supply openings are arranged at lower ends of the preheating vessels to supply the preheated raw material through the feed openings to the melting furnace body. A connecting mechanism is provided for movably connecting the supply openings with the feed openings when the melting furnace body is tilted.

Melting furnace having preheating vessel

A flicker compensating apparatus for compensating for flickering due to a variation in the reactive power generated from a DC arc furnace connected by an AC/DC converter to an AC power system, comprises: a current detector for detecting a DC current flowing in the DC arc furnace; a controller for determining the phase control angle of a thyristor included in the AC/DC converter in accordance with the difference between the detected DC current and a predetermined reference current; a calculator for calculating reactive power to be generated by the DC arc furnace, from the detected DC current, the determined phase control angle, and a no-load DC voltage; a compensator including a reactive load connected via thyristor to the power system; and a controller for controlling the phase control angle of the thyristor of the compensator in accordance with the calculated reactive power, for controlling a current flowing across the reactive load, and for permitting the compensator to generate such reactive power as to compensate for a variation in the calculated reactive power.

Flicker compensating apparatus for DC arc furnace

A method for continuous casting of steel comprises charging molten steel from a tundish into a mold through exit ports of an immersion nozzle, introducing a magnetic field vertically to a flow of the molten steel from the exit ports by the use of at least a pair of direct current magnets which are arranged on the outer side of copper plates on the wide side of the mold, the immersion nozzle being placed between the direct current magnets and polarities of magnetisms on the top side of the magnets being the same, and casting the molten steel at a predetermined casting rate. One magnetic pole of the direct current magnet is positioned at an upper end of copper plate on the wide side of the mold and the other magnetic pole being positioned at lower than the exit port of the immersion nozzle and on the outer side of copper plate on the wide side of the mold. The immersion nozzle has two exit ports, each of which has an angle of 15.degree. to 45.degree. downward. The direct current magnetic field is controlled within the range of 1000 to 4000 gauss.

Method for continuous casting of steel

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Kawasaki, Japan

Norio Ao