Kawasaki Steel Corporation

Kaku Sato

Akio Tosaka

Toshiyuki Kato

Chikako Fujinaga

Hideo Kuguminato

Yoshihiro Okawa

A method of producing a steel sheet useful for making cans. The method steps include hot-rolling a slab consisting of about 0.0005 to 0.01 wt % C, about 0.001 to 0.04 wt % N (the total of C and N is at least about 0.008 wt %), about 0.05 to 2.0 wt % Mn, about 0.005 wt % or less Al, about 0.01 wt % or less O at a finish rolling temperature within a temperature range of about the Ar.sub.3 point to about 950.degree. C., coiling the rolled material at a temperature range of about 400 to 600.degree. C., cold rolling the material, continuously annealing the material at a temperature higher than the recrystallization temperature, and then temper-rolling the material. The steel sheet exhibits good workability during can making and which can be formed into a can having high strength.

Method of producing high-strength steel sheet used for can

A method of manufacturing a cold-rolled can steel sheet having less planar anisotropy and achieving good workability. Rough-rolling is first performed on a continuously-cast slab. The slab has a composition essentially consisting of: C: 0.004 wt % or lower; Mn: 0.05-0.5 wt %; P: 0.02 wt % or lower; Al: 0.005-0.07 wt %; N: 0.004 wt % or lower; and Nb: 0.001-0.018 wt %, the rest being Fe and unavoidable impurities. A resultant sheet bar is then subjected to hot rolling which is completed at a finishing rolling temperature at an Ar.sub.3 transformation point or higher. The resultant sheet bar is coiled at a temperature range from 450.degree.-700.degree. C. Subsequently, the resultant sheet bar undergoes primary cold rolling before continuous annealing, which is performed at a recrystallization temperature or higher, and secondary cold rolling. The primary and secondary cold rolling are respectively performed at reduction ratios satisfying the following conditions of:

Method of manufacturing cold-rolled can steel sheet having less planar

A method for manufacturing a canning steel sheet with non-aging property and superior workability uses, as a starting material, an ultra-low-carbon steel slab composed of from 0.0015% to 0.0100% by weight C, up to 0.20% by weight Si, from 0.10% to 1.20% by weight Mn, from 0.02% to 0.10% by weight Al, from 0.005% to 0.040% by weight P, up to 0.015% by weight S, up to 0.005% by weight N, and balance iron and unavoidable impurities. The manufacturing method includes hot rolling the steel, cold rolling the steel at a reduction ratio not less than 70% after pickling, and recrystallization annealing the steel by using a continuous annealing furnace in an atmosphere having a hydrogen content not less than 3% and a dew point not lower than -20.degree. C. at a temperature not lower than 730.degree. C. so that the content of remained C in the steel is kept less than 0.0015% by weight. At least one element selected from Nb, Ti and B may be added in predetermined amounts to the above composition. The steel sheet suitable for canning is efficiently manufactured by a continuous annealing process.

Method of manufacturing canning steel sheet with non-aging property and

A method of manufacturing a small planar anisotropic high-strength can steel plate. Hot-rolling is first performed on a steel slab at an Ar.sub.3 transformation point or higher to obtain hot rolled steel strip. The slab has a composition which essentially consists of and which satisfies the conditions of: C.ltoreq.0.004%, Si.ltoreq.0.02%, Mn=0.5%-3%, P.ltoreq.0.02%, Al=0.02%-0.05%, 0.008%.ltoreq.N.ltoreq.0.024%, and the rest being Fe and unavoidable impurities, wherein the conditions have the relationship of:Al%/N%&gt;2. Then, the resultant strip is cooled at a cooling rate of 10.degree. C./s or higher so as to reach a temperature of 650.degree. C. or lower. The resultant strip is further coiled at a temperature in a range of from 550.degree. C. to 400.degree. C. Cold-rolling is performed on the resultant strip at a reduction ratio of 82% or higher preceded by removing a scale to obtain cold rolled steel strip. Subsequently, continuous annealing is performed on the resultant cold rolled steel strip at a recrystallization temperature or higher, being followed by temper-rolling.

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Chiba, Japan

Kaku Sato