Kawasaki Steel Corporation

Dai Nippon Toryo Co., Ltd.

Shigeko Sujita

Kazuo Mochizuki

Yasuhiro Kobayashi

Nobuyuki Morito

Kyoko Hamahara

Hirotake Ishitobi

Ujihiro Nishike

Yukio Inokuti

Ujihiro Nishiike

Osamu Ogawa

Masanori Nagai

Hiroyuki Tanabe

Norio Takahashi

Ryoichi Muko

Hisanao Nakahara

Tsuneo Nagamine

Takahiro Kusakabe

Nobuyoshi Kato

Tikara Kami

An organic composite coated steel sheet having excellent chromate dissolution resistance, wet adhesion, and corrosion resistance before and after working. The steel sheet comprises a chromate-silica film on at least one face of a zinc or zinc base alloy plated steel sheet, the silica-added chromate film having about 5 to 500 mg/m.sup.2 in terms of metal Cr content and being formed from a chromate solution containing about 25 to 70 wt % of Cr.sup.+6 based upon total Cr content. A resin coating film is adhered to the chromate-silica film and is formed from an aqueous paint. The aqueous paint includes an aqueous anionic resin and/or an aqueous nonionic resin, a reducing agent, and a water-dispersed silica. The resin coating film is deposited in a dry weight amount of about 0.1 to 3 g/m.sup.2.

Organic composite coated steel sheet

The improved organic composite coated steel plate includes a zinc or zinc alloy plated steel plate as a substrate that has on its surface a chromate film the Cr.sup.6+ content of which is no more than 70% of the total Cr content and which is deposited in an amount of 5-500 mg/m.sup.2 in terms of metallic chromium, the chromate film being overlaid with a resin layer that is deposited in an amount of 0.1-3 g/m.sup.2 on a dry weight basis and which is formed primarily of water-dispersed silica and one organic resin member as selected from the group consisting of an anionic aqueous resin, a nonionic aqueous resin and an anionic aqueous urethane resin. This steel plate is adapted for not contaminating the environment of the earth in the process of its manufacture.

Organic composite coated steel plates having improved corrosion

An organic composite coated steel strip having well-balanced corrosion resistance, coating properties including adaptability to electrophoretic coating and water resistant secondary coating adherence, and spot weldability is provided. The organic composite coated strip comprises a zinc or zinc base alloy plated steel substrate; a chromate later on the substrate containing up to 70% by weight of Cr.sup.6+ based on the total chromium quantity, the chromate layer being coated in a weight of 5 to 500 mg/m.sup.2 in terms of elemental chromium; and an organic composite layer on the chromate layer mainly comprising silica and an organic high molecular weight resin. In the organic composite coated steel strip, (a) silica has an average primary particle diameter of 5 to 30 nm; (b) silica is agglomerated into agglomerates of an average thickness of 0.2 to 2 .mu.m and an average apparent diameter of 5 to 300 .mu.m; and (c) the organic composite layer has been coated to a dry weight of 0.1 to 3 g/m.sup.2. The organic composite coated steel strip of the invention has various uses including automobile bodies.

Organic composite coated steel strip having improved corrosion

A grain oriented silicon steel sheet having a low iron loss and not causing degradation of properties even through strain relief annealing is produced by applying ultrasonic vibrations to the surface of the sheet after secondary recrystallization annealing.

Method for producing low iron loss grain oriented silicon steel sheets

A silicon-containing steel sheet having a low iron loss has such a crystal structure that crystal grains having an inclination angle of {110} face of not more than 10.degree. with respect to the sheet surface are included in an amount of not less than 80 vol % and exhibit a graining surface pattern in which boundaries of these crystal grains form stepwise difference or groove of not less than 0.4 .mu.m as a maximum height. This sheet is produced by subjecting a grain oriented silicon steel sheet after final annealing to a magnetically smoothening treatment by electrolysis in an squeous solution containing at least one of water soluble halides.

Silicon steel sheets having low iron loss and method of producing the

A grain oriented electromagnetic steel sheet having a very low iron loss is obtained by subjecting a surface of base metal in the sheet after finish annealing to a particular mechanical polishing and has a surface roughness having a center-line average roughness of not more than 0.3 .mu.m after the polishing and the number of abrasive grains embedded in a layer just beneath polished surface of not more than 20,000 grains/cm.sup.2.

Grain oriented electromagnetic steel sheets having a very low iron loss

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Chiba, Japan

Shigeko Sujita