Abstract: An aluminum or aluminum alloy-coated steel material includes base steel; and a coating layer formed on a surface of the base steel and containing by mass % Mg: 6% to 10%, Si: 3% to 7%, Fe: 0.2% to 2%, Mn: 0.02% to 2%, and the balance as Al and incidental impurities, wherein the coating layer has pseudoternary eutectic microstructures of ?Al—Mg2Si—(Al—Fe—Si—Mn) and an area ratio of the pseudoternary eutectic microstructures in the coating layer is at least 30%.

Abstract: A measuring apparatus is capable of measuring an amount of hydrogen penetrated into a metal. In the apparatus, a specimen formed of a metallic material has one surface exposed to a corrosive environment to serve as a penetration surface of hydrogen generated by a corrosion reaction while having the other surface as a hydrogen detection surface. On the hydrogen detection surface side, an electrochemical cell constituted of a plurality of cells is disposed. At least one of the plurality of cells is configured as a base cell to compensate for a residual current so that anodic currents detected in other cells than the base cell are compensated for based on the residual current detected in the base cell, and an amount of hydrogen penetrating from a corrosive surface side is calculated based on the compensated currents.

Abstract: An aluminum or aluminum alloy-coated steel material includes base steel; and a coating layer formed on a surface of the base steel and containing by mass % Mg: 6% to 10%, Si: 3% to 7%, Fe: 0.2% to 2%, Mn: 0.02% to 2%, and the balance as Al and incidental impurities, where-in the coating layer has pseudoternary eutectic microstructures of ?Al—Mg2Si—(Al—Fe—Si—Mn) and an area ratio of the pseudoternary eutectic microstructures in the coating layer is at least 30%.

Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2.ZnSO4.xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2.ZnSO4.3-5H2O.

Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2·ZnSO4·xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2·ZnSO4·3-5H2O.

Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2.ZnSO4. xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2.ZnSO4.3-5H2O.

Abstract: A method for producing a galvanized steel sheet includes contacting a steel sheet with a zinc-containing aqueous solution having a zinc ion concentration of 1 to 100 g/l, contacting the steel sheet with an aqueous solution with a pH of 6 to 14, washing the steel sheet with water, and then drying the steel sheet. An example of the zinc-containing aqueous solution is a solution containing zinc sulfate. According to the method, an oxide layer which has an average thickness of 10 nm or more and which principally contains zinc is formed on the steel sheet and the galvanized steel sheet can be stably produced at high speed in a reduced space so as to have excellent press formability.

Abstract: A method for manufacturing a galvanized steel sheet, includes: galvanizing a steel sheet; bringing the surface of the steel sheet into contact with an aqueous solution containing zinc ion in the range of 5 to 100 g/l as the zinc ion concentration, having a pH of 4 to 6, and having a liquid temperature of 20 to 70° C., holding the steel sheet for 1 to 60 seconds; and then washing and drying the steel sheet. The solution containing zinc is preferably one containing zinc sulfate, for example. According to the method, a galvanized steel sheet having an oxide layer having an average thickness of 10 nm or more and mainly containing zinc formed on the surface of the steel sheet and having excellent press formability can be stably manufactured in a short time.

Abstract: A rustproof steel sheet includes an organic and/or inorganic coating layer on at least one side thereof, the thickness of the coating layer in a portion where spot welding is performed being smaller than that of the coating layer in a portion where spot welding is not performed, and a method for manufacturing the rustproof steel sheet. Since the rustproof steel sheet has sufficiently low electric resistance at a weld spot and a satisfactory weld spot can be formed, the rustproof steel sheet has both spot weldability and corrosion resistance.

Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2.ZnSO4.xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2.ZnSO4.3-5H2O.

Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2·ZnSO4·xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2·ZnSO4·3-5H2O.