Nippon Steel Corporation

Tatsuya Kanamaru

Motohiro Nakayama

Shinichi Suzuki

Katutoshi A Arai

Yutaka Ogawa

Ryoichi Naka

Katsuyoshi Yoshida

Mitsuo Higashi

Yukimasa Suemitsu

Yukio Numakura

Junichi Morita

Hisao Hayashi

Tadafumi Honda

Takashi Hada

Katsutoshi Arai

A zinc-base galvanized sheet steel which comprises zinc-base plated sheet steel and, formed on the plating layer surface, an inorganic covering layer which contains at least one inorganic oxide in an amount of 1-500 mg/m.sup.2 in terms of the weight of metallic elements exclusive of oxygen and optionally contains at least one oxoacid or inorganic oxide colloid in an amount of 1-500 mg/m.sup.2 and further, as desired for improving weldability, a Zn oxide film formed between the inorganic covering layer and the zinc-base plating layer, and the process for producing said galvanized sheet steel.

Zinc-base galvanized sheet steel excellent in press-formability,

A galvannealed steel sheet having distinguished anti-powdering property and anti-flaking property is disclosed. The steel sheet comprises a matrix steel sheet and a galvannealed coating layer having a coating weight of 45 to 90 g/m.sup.2, composed of 8.about.12 wt. % Fe and 0.05.about.0.35 wt. %, preferably 0.05.about.0.30 wt. % Al, the balance being Zn, provided on at least one side of the matrix steel sheet, the galvannealed coating layer having a .GAMMA. phase with a thickness of not more than 1.3 .mu.m, preferably not more than 1.0 .mu.m in the region at the boundary to the matrix steel sheet, and the surface region of galvannealed coating layer has a structure either (1) .eta. and .zeta. phases do not exist in the surface region of the galvannealed coating layer, or, (2) when at least one of .eta. and .zeta. phases exist therein, the total amount of the at least one of .eta. and .zeta. phases in the galvannealed coating layer is not more than 1.5 g/m.sup.2.

Galvannealed steel sheet with distinguished anti-powdering and

A plated steel strip having an enhanced corrosion and rust resistance and an improved paint-coating property comprises a principal plating layer formed on a steel strip substrate and comprising a co-deposited zinc-chromium based alloy which comprises more than 5% by weight but not more than 40% by weight of chromium and the balance of zinc.

Corrosion resistant Zn-Cr plated steel strip

Corrosion resistant plated steel strip and method for producing same

A metallic material is electroplated with an iron-zinc alloy with an improved efficiency by using an insoluble anode and an electroplating liquid containing, in addition to necessary amounts of zinc and ferrous ions, 0.01 to 10 g/l of an additive consisting of at least one member selected from oxyalkylene compounds of the formulae (I) to (VIII), ##STR1## and ##STR2## wherein n, n.sup.1 or n.sup.5 =1 to 200,

Process for electroplating a metallic material with an iron-zinc alloy

A two layer-coated steel material having an excellent resistance to corrosion and useful for motor vehicles, has a base coating layer formed on a surface of a steel substrate and comprising zinc or a zinc-based alloy and a surface coating layer formed on the base coating layer and comprising an iron-zinc alloy containing 40% or less of zinc.

Two layer-coated steel materials and process for producing the same

A method of and an apparatus for overaging treatment of low melting point-metal plated steel band, in which a hearth roll having surface layer which consists mainly of phenol resin, mineral fiber and small quantity of additive as necessary is used under the overaging treatment temperature range and within weak oxidation, inactive or reducing high temperature gas atmosphere such that the phenol resin substantially does not oxidize and evaporate. The method and apparatus allow overaging treatment of low melting point-metal plated steel band in continuous annealing furnace having many hearth rolls to guide the steel band, and prevent the low melting point metal from being picked up on the surface of the hearth roll.

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Tokai, Japan

Tatsuya Kanamaru