Daido Tokushuko Kabushiki Kaisha

Daihatsu Motor Company, Ltd.

National University Corporation Nagaoka University of Technology

Hiroya Nakata

Hirohisa Tanaka

Tetsuo Okamoto

Saburo Sugiura

Takeshi Serizawa

Masatoshi Takeda

Koichi Niihara

Yoshio Inagaki

Tadachika Nakayama

Noboru Yamada

Senji Fujita

Etsuo Inagaki

Keiichi Mizuguchi

Atsushi Ishii

Shigeru Hanada

Satoshi Ishizawa

Kyohei Ogawa

Masashi Shida

Yoonho Kim

Disclosed are an improved method of refining steel and an apparatus for practicing the method. The refining method comprises, basically, carrying out the refining, particularly, decarburization, while stirring molten steel in the refining furnace by injecting gas thereinto, while supplying heat with a burner installed at the top of the furnace to the molten steel. According to this method, it is possible to start at an initial carbon content of the moltend steel lower than that of known AOD process, and complete the refining in a curtailed period of time and with a decreased oxidation loss of Cr. Thus, damage of refractory materials of the furnace is reduced, and the amount of Si necessary for reducing Cr-oxides in the latter stage of the refining is also reduced. Oxygen for the decarburization is supplied usually in the form of gas, but can be supplied from a solid oxygen source. In an alternative of the present method, powdery metal oxide, which is reducable equally to or more easily than Cr-oxides, is shot into the furnace through the burner or injected into the molten steel through a tuyere or an immersed lance. Preferably, the burner is of a type of variable flame length. Use of the burner disclosed here makes it possible to lengthened the flame at the former stage of the refining so that not only heat but also oxygen may be supplied to the molten steel surface of promoting the decarburization, and to shorten the flame at the latter stage of the refining so that only heat may be supplied.

Method and apparatus for refining steel

A method of operating an electric arc furnace is disclosed by which an arc electrode provided in an electric arc furnace is supplied with electric power, an electric arc is extended from the arc electrode and raw material in the electric arc furnace is molten by the arc. Before operation of the electric arc furnace, an electric current I satisfying an equation

Method of melting raw material with an electric arc furnace

Growing community of inventors

Chita, Japan

Hiroya Nakata