Nippon Kokan Kabushiki Kaisha

Takayoshi Shimomura

Kazuo Matsudo

Teruo Kurokawa

Kenji Araki

Hiroshi Kuroda

Kazuhide Nakaoka

Takao Kurihara

Haruo Kubotera

Osamu Nozoe

Shinobu Osaka

Nobuo Tanaka

Takao Arayama

Masataka Sakoh

Deep drawability and aging resistibility as required are imparted to cold rolled steel sheet by controlling the amount of C, starting temperatures of rapid cooling and cooling rate in a proposed continuous annealing process.

Continuous annealing process of producing cold rolled mild steel sheet

An enameling steel sheet characterized by a manganese content of 0.50 wt.% or under and the elimination of annealing after the final cold rolling. A satisfactory enamel adhesive property can be obtained by enameling and baking said enameling steel sheet in as-cold-rolled state after only degreasing and drying.

Enameled cold rolled sheet

In a process of making a cold-reduced steel strip for press-forming by a continuous annealing process comprising a rapid cooling step after recrystallization heating and an over-aging treatment step, when no spray of cooling water at the runout table before coiling in the hot-rolling stage is carried out on the top side and the bottom side of a travelling hot-rolled steel strip by about 20 to 200m respectively, a cold reduced soft steel sheet for press-forming is easily obtained by the above continuous annealing process.

Method of making a soft steel sheet by continuous annealing

An enameling cold rolled steel sheet with a high enamel adhesive property which requires no pickling step before enameling, characterized by an Mn content kept within 0.05 to 0.20%, and the relation between the surface roughness and the Mn content of said steel sheet satisfying at least one of the following two equations:

Enameling cold rolled steel sheet with a high enamel adhesive property

In a two stage cold reducing process, Al-stabilized steel is subjected to a decarburizing treatment as intermediate annealing between the first and second cold reducing, to impart unexpectedly high drawability to Al-stabilized steel, the drawability being more than 2.00 r (Lankford value). Such Lankford value shows that the steel is capable of sustaining any severe press forming.

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Fukuyama, Japan

Takayoshi Shimomura