Abstract: A zinc and zinc-alloy hot-dip-coated steel sheet and an alloyed zinc and zinc-alloy hot-dip-coated steel sheet, and a method for manufacturing these steel sheets, which steel sheets are used for automobiles. A zinc and zinc-alloy hot-dip-coated steel sheet which has oxides of readily oxidizable elements just under a coated layer and which shows a decreased number of bare spots and excellent coating adhesion. According to the method, the temperature for coiling during hot rolling is set to not less than 600.degree. C. and the cooling is conducted at a slow-cooling rate so that the-oxides remain after the following steps.

Abstract: The improved version of a chromated metal sheet has a chromate layer on at least one side of a metal substrate or a plated metal substrate and it is characterized in that the chromate layer has a chromium deposit of 10-200 mg/m.sup.2 per surface in terms of metallic Cr, that the chromate layer contains silica in an amount of 0.1-6.0 in terms of the weight ratio of SiO.sub.2 to Cr, and that the chromate layer contains at least one kind of lubricating particles selected from the group consisting of graphite, MoS.sub.2, BN, calcium stearate and an organic lubricating substance in an amount of 0.1-100 in terms of the weight ratio of the lubricating particles to Cr. The lubricating particles can have a surface layer capable of nonionic surface activating action, and this surface layer accounts for 1-70 wt % of the lubricating particles.

Abstract: In connection with the manufacture of zinc hot dip galvanized or galvannealed steel strip using a high strength, high tensile steel strip containing Si, Mn or Cr as a starting steel strip, the invention provides a method for hot dip galvanizing a high tensile steel strip with minimal bare spots which can manufacture a bare spot-free steel strip of quality in an inexpensive manner while minimizing process complications and lowered productivity. The invention is achieved by subjecting a cold rolled steel strip containing at least one component of 0.1 to 2.0% of Si, 0.5 to 2.0% of Mn, and 0.1 to 2.0% of Cr and optionally further containing up to 0.2% of P, in % by weight, to recrystallization annealing in a continuous annealing line, cooling the steel strip, removing a steel component concentrated layer at the surface of the steel strip by polishing and/or pickling, subjecting the steel strip again to heat reduction at a temperature from 650.degree. C.

Abstract: A method including preparing an aluminum scrap containing a total of about 0.3 to 2.0 wt % of Fe and Si; melting and then adjusting the material composition so as to attain an Mg content of about 3 to 10 wt % or a composition further containing at least one of the elements Cu, Mn, Cr, Zr and Ti, each in the amount of 0.02 to 0.5 wt %; subjecting the material to casting, hot rolling, cold rolling and continuous annealing to obtain an aluminum alloy sheet having a tensile strength of about 31 kgf/mm.sup.2 or more; and applying a lubricant surface coating to impart a coefficient of friction of not more than about 0.11.

Abstract: A blackened steel strip having improved blackness is produced in an efficient manner by anodizing a zinc alloy-plated steel strip in a solution containing 5 to 100 g/l of ClO.sub.3.sup.- and 10 to 300 g/l of SO.sub.4.sup.2- at pH 0.5 to 2.5 at a temperature of 30.degree. to 75.degree. C. and with a quantity of electricity of 10 to 300 C/dm.sup.2, and forming an acrylic resin chromate layer on the anodized steel strip to a thickness of 0.3 to 2.5 .mu.m. The solution may contain 5 to 100 g/l in total of at least one co-additive selected from Cl.sup.-, NO.sub.3.sup.-, H.sub.2 O.sub.2, Ni.sup.2+, Co.sup.2+, Fe.sup.2+, and Mn.sup.2+. The acrylic resin chromate layer contains 2 to 10 parts by weight of in the form of a chromate Cr per 100 parts by weight of acrylic resin.

Abstract: A surface-treated aluminum material comprising an aluminum or aluminum alloy substrate, a chromate film deposited on the substrate, and an organic resin mixture film deposited on the chromate film is provided. The chromate film is deposited to a coating weight of from 5 to 100 mg/m.sup.2 calculated in terms of elementary chromium on the aluminum substrate. The organic resin mixture film is deposited to a dry film thickness of from 0.05 to 3.0 .mu.m, and comprises (a) 100 parts by weight of an organic resin, (b) 0.5 to 40 parts by weight of a powder lubricant having an average particle size of from 0.05 to 20 .mu.m, said average particle size being in the range of from 1.0 to 10 folds of the dry film thickness, and (c) 1.0 to 40 parts by weight of electroconductive finely divided particles having an average particle size in the range of from 0.05 to 5 .mu.m, said average particle size being in the range of from 1.0 to 2 folds of the dry film thickness.

Abstract: A surface-treated metal sheet which excels in workability, electrical conductivity and corrosion resistance has a metal sheet which has been plated as required, a chromate layer as a first layer formed on at least one side of the metal sheet, with a deposition amount of about 5 to 200 mg/m.sup.2 as calculated on the basis of Cr, and a second layer formed on the first layer from organic lubricant particles, with a deposition amount of from about 5 to 1000 mg/m.sup.2, such that the area coated by the organic lubricant particles to the entire area of the metal sheet surface is below about 50%. The second layer is preferably applied with a roll coater, a spin coater or a dip coater, a dispersion liquid or an emulsion containing about 0.1 to 40 wt. % of the organic lubricant particles so as to provide a wet film thickness of about 0.2 to 10 .mu.m.

Abstract: The invention provides an aluminum alloy sheet having improved formability, an elongation of at least 30%, a sliding frictional resistance of up to 0.13 and minimized surface pressure dependency of sliding frictional resistance, comprising an aluminum alloy substrate containing at least 4 wt % of Mg and a Fe rich plating layer on a surface thereof in a coating weight of 1 to 50 g/m.sup.2. Also provided is a bake hardenable, surface treated aluminum alloy sheet having improved formability, an elongation of at least 25%, a sliding frictional resistance of up to 0.13 and minimized surface pressure dependency of sliding frictional resistance, comprising a bake hardenable aluminum alloy substrate containing Mg and Si in an amount of at least 0.4 wt % calculated as Mg.sub.2 Si and a Fe rich plating layer on a surface thereof in coating weight of 1 to 50 g/m.sup.2. By forming a zincate layer as an undercoat below the Fe rich plating layer, the plating adhesion is further improved.

Abstract: An electrolytic processing method for electrolytically processing the surface of a metallic member. A paste containing an electrolyte is prepared by mixing a paste-forming agent with a liquid electrolyte. The paste is placed between the metallic member and an opposing electrode. The metallic member and the opposing electrode are connected to an electrical power supply so that an electrical current is made to flow between the metallic member and the opposing electrode through the paste containing electrolyte, whereby the surface of the metallic member is electrolytically processed. Descaling, passivity treatment, coloring, polishing, plating and other electrolytic process can be performed on any type of metallic member at any desired place, by suitably selecting factors such as the compositon of the paste, condition of the electrical power supply and so forth.

Abstract: A zinc, zinc alloy or aluminum alloy plated steel strip having chromate coatings on both surfaces is coated with a lubricating resin composition for improving formability and corrosion resistance. In one form, a resin composition including a base resin, silica, a high-melting polyolefin wax and optionally, a low-melting polyolefin wax is applied on both surfaces for improving formability. In a second form, a resin composition including a base resin, silica, and a powder fluoro resin is applied on both surfaces for improving corrosion resistance. In a third form, the chromated steel is coated with a resin composition including a base resin, silica and a solid lubricant on one side and with a resin composition including a base resin and silica on the other side for improving both formability and corrosion resistance.

Abstract: An electrolytic process for forming a pattern on a metallic object makes use of a screen of electrically insulating material having a perforated pattern corresponding to the pattern to be formed on the metallic object. A paste containing an electrolyte is applied to the surface of the metallic object through the pattern of the screen. Electric current is supplied between the metallic object and an electrode placed in contact with the electrolyte-containing paste so that electrolysis takes place through the pattern of the screen on the surface of the metallic object. Disclosed also is an electrolytic apparatus suitable for use in carrying out the method.

Abstract: A black colored steel strip having improved degree of blackness and uniform appearance is prepared by subjecting a Zn-Ni alloy plated steel substrate to anodic electrolysis or alternating current electrolysis in an electrolyte solution containing at least one member selected from the group consisting of hydroxide, sulfate, and chloride of sodium, potassium, or nickel; nitrate ion; and at least one member selected from an inhibitor and a complexing agent.