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: 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.