Abstract: A coated steel sheet having excellent corrosion resistance comprises: a zinc or a zinc alloy plated steel sheet or an aluminum or an aluminum alloy plated steel sheet; a composite oxide coating formed on the surface of the plated steel sheet; and an organic coating formed on the composite oxide coating. The composite oxide coating contains a fine particle oxide and a phosphoric acid and/or a phosphoric acid compound. The organic coating has thickness of from 0.1 to 5 &mgr;m.

Abstract: A phosphate-treated steel plate comprises a zinc-base plated steel plate; a zinc phosphate coating layer formed on the surface of the zinc-base plated steel plate; and an organic or inorganic coating formed on the zinc phosphate coating layer. The organic coating comprises at least one organic resin selected from the group consisting of an ethylene-base resin, an epoxy-base resin, a urethane-base resin, and an acrylic-base resin. The inorganic coating comprises a phosphate coating consisting mainly of a phosphate.

Abstract: A production method for a lead-containing hot-galvanized chromated steel sheet with excellent resistance to blackening and white rust formation comprises: (a) plating a steel sheet in a hot-galvanizing bath containing 0.05-0.3 wt. % lead and 0.1-0.3 wt. % aluminum; (b) coating this with a chromating solution containing chromium (VI) ions, chromium (III) ions and nitrate ions in which the Cr(III)/Cr(VI) molar ratio is 1/9-1/1 and the nitrate ion to total chromium ion molar ratio is 0.1-1.6; and (c) without washing with water, drying the sheet at 40-250 deg. C., to form a 5-50 mg/m integral 2 (in terms of chromium) chromate film.

Abstract: In order to manufacture a chromate-coated lead-containing galvanized steel sheet having beautiful spangles and excellent anti-black patina and anti-white rust properties without relying upon any flushing treatment with Ni, etc., a lead-containing galvanized steel sheet obtained by plating in a galvanizing bath containing appropriate amounts of Pb and Al, and having beautiful spangles is coated with a chromate coating solution containing trivalent and hexavalent chromium ions in a molar ratio of 1/9 to 1/1, and nitrate ions in a molar ratio of 0.1 to 1.6 to the total of the chromium ions, preferably after treatment with an aqueous alkali solution having a pH of 9 or above, and washing with water, and the sheet is dried at an appropriate sheet temperature without being washed with water, whereby a chromate film having a coating weight of 5 to 50 mg/m2 is formed thereon.

Abstract: Disclosed is an optical fiber-housing metal pipe, comprising a base body of an optical fiber-housing metal pipe, an aluminum layer formed on the surface of the base body, and an oxide layer formed on the aluminum layer, the oxide layer serving to improve the corrosion resistance and wear resistance of the optical fiber-housing metal pipe. Also disclosed is an optical fiber-housing metal pipe comprising a base body of an optical fiber-housing metal pipe, an Al-X alloy layer formed on the surface of the base body, where X is one or two kinds of elements selected from the group consisting of Mn, Ti, Ni, Cr, Nb, Mg, Fe, In and Sn, or an Al-based composite layer containing at least one kind of a material selected from the group consisting of a carbide, an oxide and an organic compound.

Abstract: The invention relates to a thermosetting coating composition for precoated steel sheets which are required to have high hardness, good workability and stain resistance, to a precoated steel sheet having a film of the coating composition, and to a method for producing such precoated steel sheets.

Abstract: A zinciferous coated steel sheet comprises a steel sheet, a zinciferous coating layer formed on the steel sheet, a Fe--Ni--Zn--O film formed on the zinciferous coating layer, and an oxide layer formed on a surface portion of the Fe--Ni--Zn--O film. The method comprises providing an electrolyte of an acidic sulfate aqueous solution, carrying out an electrolysis treatment in the electrolyte under a current density ranging from 1 to 150 A/dm.sup.2, and carrying out an oxidation treatment to a surface of the zinciferous coated steel sheet.

Abstract: It is an object to provide a process for manufacturing galvannealed steel sheets exhibiting excellent anti-powdering property when press formed, and uniform frictional properties in a coil. A steel strip is galvanized in a bath having a low aluminum content after entering it at a high temperature as defined in relation to the aluminum content of the both, so that the formation of a .zeta. phase may be promoted. Then, the strip is heated for alloying in a high-frequency induction heating furnace so as to have a temperature not exceeding 495.degree. C. when leaving the furnace to yield a plated steel strip having a coating containing a uniformly distributed .zeta. phase. After such heat treatment and cooling, the strip can be plated with an iron or iron-alloy top coating having an iron content of at least 50% and a coating weight of at least 1 g/m.sup.2 to achieve an improved press formability.

Abstract: It is an object to provide a process for manufacturing galvannealed steel sheets having high anti-powdering property as required when they are press formed, and stabilized frictional properties in a coil. Steel sheets are plated in a bath having a low aluminum content, while they have, when entering the bath, a low temperature as defined in relation to the aluminum content of the bath, so that an alloying reaction may be prevented. Then, the sheets are heated for alloying in a high-frequency induction heating furnace so that the sheets leaving the furnace may have a temperature of from over 495.degree. C. to 520.degree. C. to yield galvannealed consisting mainly of a .delta..sub.1 phase. An iron or iron-alloy top coating having an appropriate iron content can be applied onto the plated steel surface to improve its paintability.

Abstract: A method for manufacturing an iron-zinc alloy plated steel sheet having two plating layers and excellent in electropaintability and press-formability, which comprises the steps of: applying an alloying treatment under a temperature of from 420.degree. to 520.degree. C. to a zinc dip-plated steel sheet to form on the surface of the steel sheet an alloying-treated iron-zinc alloy dip-plating layer having on the surface thereof fine irregularities comprising numerous fine concavities and numerous fine convexities; then applying a temper rolling treatment at a reduction rate of from 0.3 to 1.

Abstract: A method for manufacturing an iron-zinc alloy plated steel sheet having two plating layers and excellent in electropaintability and press-formability, which comprises the steps of: passing a steel sheet through a zinc dip-plating bath to form a zinc dip-plating layer on at least one surface of the steel sheet; then, heating the steel sheet, on which the zinc dip-plating layer has been formed, to alloy the zinc dip-plating layer and the surface portion of the steel sheet, so as to form, on the surface thereof, an alloying-treated iron-zinc alloy dip-plating layer as a lower layer having a plating weight of from 30 to 120 g/m.sup.

Abstract: A method for manufacturing a zinciferous electroplated steel sheet excellent in press-formability, which comprises the steps of: electroplating a steel sheet in a zinciferous acidic electroplating solution, which contains nitric acid ions or nitrous acid ions in an amount within a range of from 0.1 to 50 g per liter of the electroplating solution, and oxide particles of a metal or a semimetal, uniformly dispersible into the electroplating solution, in an amount within a range of from 0.1 to under 0.5 g per liter of the electroplating solution, to form, on at least one surface of the steel sheet, a zinciferous electroplating layer in which zinc hydroxide particles having the oxide particles as nuclei thereof are uniformly dispersed.

Abstract: An electroplated steel sheet having a plurality of coatings, excellent in workability, corrosion resistance and water-resistant paint adhesivity, which comprises:an iron-chromium-zinc alloy coating as a lower layer, having a coating weight of from 0.1 to 40 g/m.sup.2 per side, formed on the surface of a steel sheet, consisting essentially of:iron: from 3 to under 15 wt. %,chromium: from 0.1 to 1 wt. %, andthe balance being zinc and incidental impurities;another iron-chromium-zinc alloy coating as an intermediate layer, having a coating weight of from 20 to 59.9 g/m.sup.2 per side, formed on the iron-chromium-zinc alloy coating as the lower layer, consisting essentially of:iron: from 10 to 40 wt. %,chromium: from over 1 to under 30 wt.

Abstract: An apparatus for removing, by means of a scraper, an electroplating metal deposited onto the surface of a conductor roll for electroplating. The above-mentioned removal is accomplished by pressing the scraper (23) arranged near the conductor roll (5) against the conductor roll (5). The start and the end of the removal can properly be controlled on the basis of a value of potential difference between a reference electrode (21) immersed in the electroplating solution and the conductor roll (5), as measured by means of a potentiometer (25). The scraper (23) return-travels, together with the reference electrode (21), in the axial direction of the conductor roll (5) by the action of a scraper moving mechanism (30).

Abstract: A composite electroplated steel sheet comprises Zn being a matrix metal of a plating layer; and codeposited particles of a plating layer of at least one selected from the group consisting of Mg.sub.2 Si.sub.3 O.sub.8, CaSiO.sub.3 and BaTiO.sub.3. A composite electroplated steel sheet comprises Zn alloy containing at least one selected from the group consisting of Fe, Co, Ni, Mn, Cr and Ti being a matrix metal of a plating layer; and codeposited particles of a plating layer comprising at least one selected from the group consisting of Mg.sub.2 Si.sub.3 O.sub.8, CaSiO.sub.3 and BaTiO.sub.3. The codeposited particles are contained within the range of from 0.1 to 5.0 wt.% in a plating layer.

Abstract: A vertical type electro-galvanizing apparatus, which comprises: a U-shaped electro-galvanizing tank including a first vertical path (12) at a steel strip inlet side, a second vertical path (13) at a steel strip outlet side and a horizontal path (14) for communicating the lower end of the first vertical path (12) to the lower end of the second vertical path (13); a first conductor roll (2), arranged above the first vertical path (12), for directing a steel strip (5) downwardly into the first vertical path (12) and applying electricity to the steel strip (5); at least one sink roll (3, 3'), arranged in the horizontal path (14), for upwardly reversing the travelling direction of the steel strip (5); a second conductor roll (4), arranged above the second vertical path (13), for directing the steel strip (5) upwardly from the second vertical path (13) and applying electricity to the steel strip (5); at least one first electrode plate (6, 6) arranged in the first vertical path (12); at least one second electrode pl

Abstract: An iron-zinc alloy electro-galvanized steel sheet having a plurality of iron-zinc alloy coatings, which comprises: at least one iron-zinc alloy coating as the lower layer, formed on the surface of a steel sheet, and at least two iron-zinc alloy coatings as the upper layer, formed on the at least one iron-zinc alloy coating as the lower layer. The ratio of iron content to the coating weight of each of the at least one iron-zinc alloy coating as the lower layer is within the range of from 1 to 15 wt. %, and the total coating weight of the at least one iron-zinc alloy coating as the lower layer is within the range of from 1 to 50 g/m.sup.2 per side of the steel sheet. The ratio of iron content to the coating weight of each of the at least two iron-zinc alloy coatings as the upper layer is over 15 wt.