Kawasaki Steel Corporation

Shigeru Yoshida

Yasuyuki Hayakawa

Ujihiro Nishiike

Bunjiro Fukuda

Yoh Shimizu

Norihisa Shiraishi

Masataka Yamada

Chosei Asakawa

Tetsuya Oishi

Morohira Sakaguchi

Method of manufacturing a grain oriented silicon steel sheet. An annealing separating agent mainly composed of MgO is coated on a surface of a decarburized silicon steel sheet. The silicon steel sheet is subjected to secondary recrystallization annealing and then purification annealing. The annealing separating agent contains Ti oxide or a Ti compound which can be oxidized by heating. The purification annealing is conducted in steps. A non-oxidizing atmosphere having a high nitrogen concentration is present in one step. A hydrogen atmosphere having a low nitrogen concentration is present in a subsequent step.

Method of manufacturing grain oriented silicon steel sheets

A rotary hearth finish annealing furnace includes coil tables carrying thereon steel plate coils to be annealed with their axes being vertical, a hearth traveling along a circle having a predetermined radius and supporting thereabove the coil tables, inner covers covering the coils on the coil tables, and a protective cover covering the above members over a predetermined distance. According to the invention, heating means for heating the coils are arranged at a level above upper ends of the steel plate coils. In a preferred embodiment, the coil tables are arranged so as to permit the coils to be arranged thereon in at least two circular rows on a single plane concentric to said traveling circle of the hearth. Moreover, portions of the hearth subjected to loads of the coils and coil tables are made of comparatively high strength bricks and the other portions are made of a light weight refractory material. With these arrangement, the furnace according to the invention operates with a high thermal efficiency to greatly save the energy required for its operation.

Rotary hearth finish annealing furnace

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Kurashiki, Japan

Shigeru Yoshida