Nippon Steel Corporation

Japan Metals & Chemicals Co., Ltd.

Hidetake Ishikawa

Hiroyuki Katayama

Chikara Saito

Masaki Fujita

Masatoshi Kuwabara

Yasushi Nakamura

Takashi Shimanuki

Takamasa Ohno

Hiroyuki Kajioka

Kenji Shibata

Michihisa Itou

Hirofumi Wakimoto

Tuneyuki Inoue

Yoshiaki Tamura

There is provided a process for producing a high-manganese iron alloy from a manganese ore and/or a pre-reduced product thereof in a top and bottom blown converter type reaction vessel holding molten iron or a molten manganese iron alloy, together with a molten slag, said molten iron or alloy and said molten slag being the products of a separate smelting furnace, gas being blown into said vessel through a bottom blowing nozzle, said process comprising charging said vessel with a supply of raw materials including at least one source of manganese and iron selected from a manganese ore containing manganese oxide and iron oxide and a pre-reduced product thereof, a solid carbonaceous substance and a slag forming agent, while simultaneously blowing gas selected from oxygen and a gas containing oxygen into said vessel through a top blowing lance to burn said carbonaceous substance so as to heat, melt and reduce said raw materials to form a melt containing manganese oxide and iron oxide; supplying an additional carbonaceous substance into said melt to reduce said manganese oxide and said iron oxide to form a molten high-manganese iron alloy and a molten slag, discontinuing said blowing of gas through said top blowing lance, and removing said molten high-manganese iron alloy and said molten slag from said vessel, said molten alloy being used for casting.

Process for production of high-manganese iron alloy by smelting reduction

A process which enables high-chromium alloy such as ferrochromium heretofore obtained by the use of electricity to be produced less expensively in higher yield of chromium by the smelting reduction using solid carbonaceous material such as coke in the place of electricity. The process of smelting reduction is so performed in the top and bottom blowing converter divided into two stages: the first stage for carrying out the converter operation under continued supply of the raw materials containing pre-reduced chromium oxide (chromium ore) and the second stage for carrying out the converter operation under suspended supply of the raw materials containing the pre-reduced chromium oxide, and the first stage of converter operation is carried out under conditions such that the temperature of the molten metal remains at or below 1,650.degree. C. and the ratio of the volume of the gas generated per minute by the substances supplied through the tuyere for bottom blowing to the combined weight of the molten metal and the molten slag falls in the range of 100 to 2,500 [Nl/min.t] and the second stage of converter operation is carried out under conditions such that the temperature of the molten metal remains at or below 1,650.degree. C., the ratio of the volume of gas generated per minute by the substances supplied through the tuyere for bottom blowing to the combined weight of the molten metal and the molten slag falls in the range of 100 to 1,800 [Nl/min.t].

Process for production of high-chromium alloy by smelting reduction

A process for producing high chromium steel is disclosed which comprises supplying molten iron in a smelting furnace with a solid chromium source, carbonaceous powder and oxygen-containing gas in amounts so controlled as to keep the melt at a temperature in the range of less than 1650.degree. C. and above the minimum melt temperature at the specific carbon and chromium levels in the melt and which is capable of performing preferential decarbonization while inhibiting the oxidation of chromium.

Process for producing high chromium steel

Cr alloy, Mn alloy or Mo alloy can be dephosphorized and denitrified simultaneously with a flux newly prepared. The flux comprises metallic Ca, Mg, Ba or Sr and halides thereof. There is no loss of valuable alloying component in this method.

Method for dephosphorization and denitrification of an alloy containing

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Fukuoka-ken, Japan

Hidetake Ishikawa