Nippon Steel Corporation

Motohiro Nakayama

Tatsuya Kanamaru

Katutoshi A Arai

Shinichi Suzuki

Ryoichi Naka

Kazutsugu Nakajima

Yutaka Ogawa

Masato Yamada

Motofumi Kurahashi

Katsuyoshi Yoshida

Masanori Takemoto

Mitsuo Higashi

Yukimasa Suemitsu

Tetsuya Nishiura

Yukio Numakura

Hiroyuki Kawano

Hisao Hayashi

Tadafumi Honda

Steel sheet excellent in coating sharpness, defect-formation resistance

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 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.

Method for heat treatment of low melting point-metal plated steel band

A steel sheet having a zinc coating on one side and a uniformly alloyed layer of iron and zinc on the other side, the amount of the alloyed layer being from 0.001 g/m.sup.2 to 1 g/m.sup.2 of zinc and containing from 6 to 20 percent by weight iron.

Steel sheet having a zinc coating on one side

A method for producing a one-side zinc plated steel sheet, comprising;

Method for producing a steel sheet having a zinc coating on one side

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Tokai, Japan

Motohiro Nakayama