Sumitomo Metal Industries, Inc.

Seiichi Masuda

Hidemasa Nakajima

Shozo Okamura

Tohru Matsuo

Takeyuki Hirata

Masanobu Sueyasu

Katsukiyo Marukawa

Syoji Anezaki

Tsutomu Tanaka

Shoji Anezaki

Koji Okane

Nobuyoshi Hiroki

Takeo Aoki

Masayuki Taga

Koichi Tanaka

Yoichi Umeda

Yoshimichi Ohkita

A process for refining high-Cr steel, e.g. 13% Cr steel and 18% Cr steel, is disclosed. The process comprises preparing molten iron in a top-and-bottom blowing converter, heating the molten iron to a predetermined temperature, effecting the decarburization of the thus prepared molten iron by blowing oxygen gas through a top lance against the surface of the molten iron to provide a molten steel while, as bottom-blown gas, initially introducing an oxygen-containing gas into the molten steel then changing to an inert gas when the carbon content of said molten steel is reduced to a predetermined level so as to suppress the oxidation of chromium, and tapping the resulting molten steel out of the converter after adjusting the steel composition.

Process for refining high-chromium steels

A process for producing an ultra-low phosphorus steel containing 0.010% or less of phosphorus is disclosed, which comprises charging a desiliconized pig iron into a top- and bottom-blowing oxygen converter, introducing a slag-forming agent in a powdered form onto the molten iron together with the top-blowing oxygen and introducing a bottom-blowing gas selected from the group consisting of an inert gas, nitrogen gas, oxygen gas, carbon monoxide gas, carbon dioxide gas and mixtures thereof during the oxygen top-blowing or during both the oxygen top-blowing and the subsequent tapping.

Production of ultra-low phosphorus steel

In a process for gasification of solid carbonaceous material such as coal, powdered coal is top-blown onto a molten iron bath stored in a furnace through a non-submerged lance toward a hot spot formed by means of a jet of oxygen and steam top-blown through a non-submerged lance, the coal being blown by means of a carrier gas, and flux is optionally added into the furnace by the lump or blown toward the hot spot, thereby resulting in the coal being gasified. The ratio L/L.sub.o of the depression depth L of the molten iron bath to the molten iron bath depth L.sub.o is maintained from 0.05 to 0.15, and the blowing velocity of the solid carbonaceous material is maintained from 50 to 300 m/sec so as to suppress the formation of an adhered mass on the upper part of the furnace, hood or lance.

Process for gasification of solid carbonaceous material

A process for making carbon steel and low-alloy steel in a basic oxygen furnace is disclosed, which comprises preparing a molten metal suitable for producing the steel in said basic oxygen furnace, carrying out the top-blowing of oxygen gas and bottom-blowing of carbon dioxide gas and then tapping the resulting molten steel. The top-blowing oxygen gas is injected through a lance onto the molten metal at an outlet velocity of Mach 0.8-2.0.

Steel making process

An oxygen top-blowing steelmaking process is disclosed, which comprises preparing a molten metal suitable for producing steel in a basic oxygen furnace, carrying out the top-blowing and bottom-blowing and then tapping the resulting molten steel. The bottom-blowing is carried out at least partly during the period of time from beginning of blowing to the tapping of the melt and a powder of a slag-forming agent, such as quick lime, limestone, is introduced into the molten metal together with the top-blowing of oxygen jet injected through an oxygen lance so as to form an effective slag at an early stage of refining.

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Nishinomiya, Japan

Seiichi Masuda