Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Nippon Steel & Sumikin Coated Sheet Corporation

Yoshihiro Suemune

Kazuhiko Honda

Hiroyasu Furukawa

Hiroshi Kanai

Katsunori Tobisawa

Kohei Ueda

Koki Tanaka

Akira Takahashi

Yasuhide Morimoto

Tooru Oohashi

Hidetoshi Hatanaka

Tsuyoshi Miyake

Magonori Nagase

Jun Maki

Wataru Yamada

Masao Kurosaki

Shigenori Tanaka

Satoru Tanaka

Hidetoshi Shindo

Nobuyuki Shimoda

Kazumi Nishimura

Yoichi Ikematsu

Hiromasa Nomura

Tetsuo Nishiyama

Takeo Itoh

Shiro Fujii

Masaaki Sugiyama

Nobuki Shiragaki

Yoko Amano

Shinichi Fukuoka

Kengo Yoshida

Kenji Inada

Yoshikazu Yamanaka

A gas wiping apparatus includes a pair of wiping nozzles which are disposed so as to face each other and interpose a coated steel sheet therebetween in a thickness direction of the coated steel sheet, and each of which ejects a wiping gas along a width direction of the coated steel sheet; a gas shield plate that is disposed at a position which separates toward an outside from each end portion of the coated steel sheet so that the gas shield plate is interposed between the pair of wiping nozzles; and a side nozzle that ejects a gas to form a gas flow along each surface of the gas shield plate in a direction reverse to a direction in which the coated steel sheet is pulled upward.

Gas wiping method and gas wiping apparatus

The present invention provides a hot-dipped steelthat demonstrates favorable corrosion resistance and formability, and has a favorable appearance of a plating layer. The hot-dipped steel of the present invention includes a steel substrate formed thereon with an aluminum-zinc alloy plating layer. The aluminum-zinc alloy plating layer contains Al, Zn, Si and Mg as constituent elements thereof and the Mg content is 0.1% to 10% by weight. The aluminum-zinc alloy plating layer contains 0.2% to 15% by volume of an Si&#x2014;Mg phase, and the weight ratio of Mg in the Si&#x2014;Mg phase to the total weight of Mg is 3% or more.

Hot-dipped steel and method of producing same

A precoated metal sheet produced by simultaneous multilayer coating, and a process for producing the same, is provided with improved color shading prevention and adhesion. In the precoated metal plate, the centerline average roughness Ra in the coating film interface is not less than 0.3 &#x3bc;m, and the maximum height from the waviness center line in the interface is not more than 50% of the layer thickness. Also provided is (i) a top clear coated metal plate, which comprises a clear layer as an upper layer, has an interfacial centerline average roughness Ra of 0.3 to 0.7 &#x3bc;m and has excellent weathering resistance; and (ii) a precoated metal plate having excellent processability and corrosion resistance, which contains not less than 30% by mass of a rust preventive pigment.

Precoated metal sheet and method of production of precoated metal sheet

Hot dip galvanized steel sheet excellent in shapeability and plateability comprised of high strength steel sheet according to the present invention can be provided containing, by mass % about, C: 0.05 to 0.25%, Si: 0.3 to 2.5%, Mn: 1.5 to 2.8%, P: 0.03% or less, S: 0.02% or less, Al: 0.005 to 0.5%, N: 0.0060% or less and the balance of Fe and unavoidable impurities. The exemplary steel sheet can have thereon a galvanized layer containing, e.g., about Al: 0.05 to 10 mass % and Fe: 0.05 to 3 mass % and the balance of Zn and unavoidable impurities. Such exemplary hot dip galvanized steel sheet can have oxides containing Si in an average content of about 0.6 to 10 mass % at the crystal grain boundaries and in the crystal grains at the sheet steel side 5 &#x3bc;m or less from the interface between the high strength steel sheet and the plating layer and by the presence of Fe&#x2014;Zn alloy with an average grain size of about 0.5 to 3 &#x3bc;m at the plating side.

High strength hot dip galvanized steel sheet and high strength galvannealed steel sheet excellent in shapeability and plateability

The invention provides a method of applying a mutilayer coating film, in which two or more layers of coating are applied to a flat plate, such as steel plate; and a product with multilayer coating film obtained by the method. The method includes discharging paint films through multiple slits, simultaneously applying these films to a traveling plate to thereby form a multilayer paint film and carrying out drying or baking thereof, characterized in that the boiling point of the solvent contained in the layer close to the plate is equivalent to or lower than the boiling point of solvent contained in the layer remote from the plate, and that the boiling point of solvent contained in the layer closest to the plate is lower than the boiling point of solvent contained in the layer remotest from the plate.

Method for coating a multilayer film and product having a multilayer coated film

A method of applying a multilayer coating film, in which two or more layers of coating film are applied to a flat plate, such as steel plate, by baking finish, which method is effective for preventing of foam generation; and a product with multilayer coating film obtained by the method. There is provided a method of applying a multilayer coating film, including discharging paint films through multiple slits, simultaneously applying these films to a traveling plate to thereby form a multilayer paint film and carrying out drying or baking thereof, characterized in that with respect to the boiling points of solvents contained in adjacent layers of the multilayer paint film, there is such a relationship that the boiling point of solvent contained in the layer close to the plate is equivalent to or lower than the boiling point of solvent contained in the layer remote from the plate, and that the boiling point of solvent contained in the layer closest to the plate is lower than the boiling point of solvent contained in the layer remotest from the plate.

The object of the present invention is to provide a plated steel sheet capable of securing excellent post-painting corrosion resistance and brightness, and the present invention makes it possible to produce a plated steel sheet excellent in post-painting corrosion resistance and paint coat image clarity by further adding one or more elements selected from among 0.01 to 0.5% of Ca, 0.01 to 0.2% of Be, 0.0001 to 0.2% of Ti, 0.1 to 10% of Cu, 0.001 to 0.2% of Ni, 0.01 to 0.3% of Co, 0.0001 to 0.2% of Cr and 0.01 to 0.5% of Mn, in mass, to the plated layer of the plated steel sheet which is characterized in that the center line average roughness Ra of the Zn alloy plated steel sheet is 1.0 &#x3bc;m or less and the filtered waviness curve Wthereof is 0.8 &#x3bc;m or less, the Zn alloy plated steel sheet having on the surface thereof the plated layer containing 1 to 10% of Mg, 2 to 19% of Al and 0.001 to 2% of Si in mass and other elements the total amount of which is suppressed to 0.5% or less in mass, with the balance consisting of Zn.

Zinc-plated steel sheet excellent in corrosion resistance after coating and clarity of coating thereon

The present invention provides a plated steel material, said plated steel material having a plated layer which contains Al of 4% or more in mass, excellent in surface smoothness even when a cooling rate is low. In the present invention: a plated layer which contains Al of 4% or more in mass and has an Al-type intermetallic compound in an Al phase or abutting on an Al phase is formed on the surface of a steel material; in particular, high corrosion-resistance is secured in various environments by using a plated layer containing Al of 4 to 20% and Mg of 1 to 10% in mass with the balance consisting of Zn and unavoidable impurities or a plated layer containing Al of 4 to 20%, Mg of 1 to 10% and Si of 0.001 to 2% in mass with the balance consisting of Zn and unavoidable impurities; said plated layer contains an intermetallic compound having a melting point of 600&#xb0; C. or higher by 0.001 to 0.5% in mass; and a plated steel material having an excellent surface smoothness is obtained by using an Al-type intermetallic compound wherein at least one of the lattice constants is in the range from 3 to 5 &#x212b;.

Highly corrosion-resistant hot dip plated steel material excellent in surface smoothness

A coated steel material excellent in corrosion resistance and a method of producing the same, wherein a coated steel material has on the surface of the steel sheet a Zn-alloy coating layer containing 1-10 wt % of Mg, 2-19 wt % of Al and 0.01-2 wt % of Si, where Mg and Al satisfy Mg (%)&plus;Al (%)&lE;20%, the balance being Zn and unavoidable impurities, and has a coating layer structure of a Mg intermetallic compound or the like. As a base metal treatment, it is preferably provided with a Ni coating layer. The coated Zn-alloy coated steel sheet may have provided on the coating layer, as an intermediate layer, a chromate film layer, and, as an upper layer, an organic coating layer. The Zn-alloy coating layer may further contain one or more of 0.01-1 wt % of In, 0.01-1 wt % of Bi and 1-10 wt % of Sn. The coated steel material may be painted.

-Zn coated steel material, ZN coated steel sheet and painted steel sheet excellent in corrosion resistance, and method of producing the same

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Kimitsu, Japan

Yoshihiro Suemune