Kawasaki Steel Corporation

Shinobu Okano

Koichi Hashiguchi

Akio Tosaka

Masahiko Morita

Hajime Kimura

Yuko Takeuchi

Yuki Nakahara

Kei Sakata

Toshihiko Emi

Osamu Haida

Shuji Watanabe

Toshio Iwasaki

Hiroshi Ooi

Akitoshi Fujiwara

Toshiaki Shiraishi

Noboru Okamoto

A laminar flow cooling system employs a laminar flow nozzle comprising a pair of plate members defining slit through which cooling water flows to form a cooling water screen. One of the plate members of the laminar nozzle is deformable at least in a direction perpendicular to the cooling water flow direction to adjust the path area in the nozzle. At least one of the plate member is preferably responsive to the cooling water pressure to cause variation of the path area for adjusting the cooling water path area.

Method and system for cooling strip

A chromate-treated steel strip comprising a chromate film on a zinc plated steel strip is improved in corrosion resistance and coating adherence by forming the chromate film of three layer structure consisting of a metallic Cr layer, a Cr.sup.3+ oxide layer, and an outermost surface layer of SiO.sub.2, and Cr.sup.3+ oxide plus Cr.sup.6+ oxide. The three layered chromate film is deposited on a zinc plated steel strip by effecting cathodic electrolysis in a bath containing hexavalent chromium, colloidal silica, optional alumina sol, and a fluoride, by supplying electricity at a specific current density to a controlled quantity.

Chromate-treated zinc-plated steel strip and method for making

A method of manufacturing a cold-rolled steel sheet having a good deep drawability is disclosed, wherein a hot rolled steel sheet having a composition of C.ltoreq.0.0035%, Si.ltoreq.1.0%, Mn.ltoreq.1.0%, Al:0.005-0.10%, P.ltoreq.0.15%, N.ltoreq.0.0035%, S.ltoreq.0.015%, Ti: (48/14N(%)+48/32S(%)) or {4.times.(C(%)+N(%))}.about.(3.48/12C(%)+48/14N(%)+48/32S(%)) and Nb: (0.2.93/12C(%)).about.(93/12C(%))% is cooled within 2 seconds after the completion of finisher rolling and then at an average cooling rate of not less than 10.degree. C./sec until it arrives at a coiling step, and then the cooled steel sheet is coiled at a temperature of not more than 710.degree. C., subjected to a cold rolling at a reduction of not less than 50%, which was subjected to a continuous annealing in a heatcycle inclusive of heating from 400.degree. C. to 600.degree. C. at a heating rate of not less than 5.degree. C./sec and soaking at a temperature range of 700.degree. C.-Ac.sub.3 point for 1 second or more.

Method of manufacturing a cold-rolled steel sheet having a good deep

A chromate-treated steel strip comprising a chromate film on a zinc plated steel strip is improved in corrosion resistance and coating adherence by forming the chromate film of three layer structure consisting of a metallic Cr layer, a Cr.sup.3+ oxide layer, and an outermost surface layer of SiO.sub.2 and Cr.sup.3+ oxide plus Cr.sup.6+ oxide plus Cr.sup.6+ oxide. The three layered chromate film is deposited on a zinc plated steel strip by effecting cathodic electrolysis in a bath containing hexavalent chromium, colloidal silica, optional alumina sol, and a fluoride, by supplying electricity at a specific current density to a controlled quantity.

Steel materials having an excellent hydrogen induced cracking resistance when used under atmosphere containing H.sub.2 S, which contain 0.05 to 0.20% of C, 0.01 to 0.50% of Si, 0.60 to 2.00% of Mn, 0.01 to 0.10% of Al, less than 0.0020% of S, Ca of 0.0020% to less than 0.0050%. These steel materials are increased in the tensile strength by additionally containing at least one of Cu, Ni, Cr, B, Mo, Nb, V, Zr and Ti. Furthermore the effect of addition of Ca is stabilized by adding rare-earth elements.

Steel materials having an excellent hydrogen induced cracking resistance

Growing community of inventors

Chiba, Japan

Shinobu Okano