A grain-oriented electrical steel sheet according to the present invention includes a silicon steel sheet as a base steel sheet, and when an average value of amplitudes in a wavelength range of 20 to 100 μm among wavelength components obtained by performing Fourier analysis on a measured cross-sectional curve parallel to a sheet width direction of the silicon steel sheet is set as ave-AMP.sub.C100, ave-AMP.sub.C100 is 0.0001 to 0.050 μm.

The present invention is in the field of chemical cleaning and surface treatments for a stainless steel substrate. In particular, the present invention provides a method, kit and use of specific solutions for removing rouging (class I, II and/or III) and/or blacking from a stainless steel substrate, which may be used as processing station or production unit.

The present invention has as its object the provision of a coated steel member and coated steel sheet excellent in hydrogen embrittlement resistance in a corrosive environment and methods for manufacturing the same. The coated steel member of the present invention is provided on its surface with an Al—Fe-based coating containing Cu and one or more of Mo, Ni, Mn, and Cr in a total by mass % of 0.12% or more by heating, cooling, and manufacturing a coated steel sheet having a layer containing Cu on its surface under predetermined conditions.

A high strength steel sheet comprising a center part of sheet thickness and a surface soft part formed at one side or two sides of the center part of sheet thickness, having metal structures of the center part of sheet thickness comprising, by area ratio, tempered martensite: 85% or more, one or more of ferrite, bainite, pearlite, and retained austenite: total of less than 15%, and as-quenched martensite: less than 5%, and additionally having metal structures of the surface soft part comprising, by area ratio, ferrite: 65% or more, pearlite: 5% or more and less than 20%, one or more of tempered martensite, bainite, and retained austenite: total of less than 10%, and as-quenched martensite: less than 5%, wherein a Vickers hardness (Hc) of the center part of sheet thickness and a Vickers hardness (Hs) of the surface soft part satisfy 0.50≤Hs/Hc≤0.75.

[Object]

To provide a roughened nickel-plated material in which the formation unevenness such as generation of the unevenness or grooves in a roughened nickel plated layer is restrained.

[Solving Means]

A roughened nickel-plated material including a base material that is a rolled material, and a roughened nickel plated layer formed on at least one surface of the base material, in which SRzjis of the surface of the roughened nickel plated layer is equal to or more than 2 μm, and, letting a maximum height of the roughened nickel plated layer be SRz, a valley region B in a given virtual planer region A as observed at a height position of SRz×0.25 satisfies the following (i). (i) The length of the valley region B in the rolling direction RD of the base material is less than 40 μm in a direct distance.

The high-strength thin steel sheet has a chemical composition containing C, Si, Mn, P, S, Al, and N, with the balance being Fe and inevitable impurities, and a complex structure containing ferrite, tempered martensite, and bainite, where a volume fraction of a total of tempered martensite and bainite containing five or more carbides with a particle size of 0.1 μm or more and 1.0 μm or less in a grain with respect to a total of the tempered martensite and the bainite is 85% or more, and C mass % and Mn mass % in a region of 20 μm or less in a thickness direction from a surface of the steel sheet are each 20% or less with respect to C mass % and Mn mass % in a region of 100 μm or more and 200 μm or less from the surface of the steel sheet.

Provided is a ferritic stainless steel sheet for current collectors for sulfide-based solid-state batteries, which has excellent sulfidation resistance and adhesiveness. The ferritic stainless steel sheet has a component composition containing Cr in an amount of 16% by mass or more, wherein the surface of the ferritic stainless steel sheet has an uneven structure having recessed portions and projecting portions, the average height of the projecting portions is 20 to 50 nm inclusive, the average distance between the projecting portions is 20 to 200 nm inclusive, and the [Cr]/[Fe], i.e., the ratio of the atom concentration of Cr that is present in a form other than the metal form to the atom concentration of Fe that is present in a form other than the metal form, on the surface of the ferritic stainless steel sheet is 1.0 or more.

The present invention relates to a method of cleaning pretreatment of ferrous components that have been joined by welding, in which residues from the welding operation are removed from the surface of the component and, in this way, subsequent wet-chemical conversion treatments are enabled so as to produce defect-free coatings. For cleaning pretreatment, the component is contacted with an aqueous sulfuric acid etchant which comprises amino alcohols, ethoxylates and/or propoxylates of fatty alcohols having 6 to 12 carbon atoms in the alcohol and iron ions, and is effective without the presence of fluorides. In a further aspect, the present invention encompasses an aqueous acidic etchant for cleaning pretreatment of ferrous components that have been joined by welding.

A grain oriented electrical steel sheet includes a base steel sheet, an oxide layer, and a tension-insulation coating. When a glow discharge spectroscopy is conducted in a region from a surface of the tension-insulation coating to an inside of the base steel sheet, a sputtering time Fe.sub.0.5 at which a Fe emission intensity becomes 0.5 times as compared with a saturation value thereof and a sputtering time Fe.sub.0.05 at which a Fe emission intensity becomes 0.05 times as compared with the saturation value satisfy 0.01<(Fe.sub.0.5−Fe.sub.0.05)/Fe.sub.0.5<0.35. Moreover, a magnetic flux density B8 in a rolling direction of the grain oriented electrical steel sheet is 1.90 T or more.

The present invention provides a chromium-containing steel sheet for a current collector of a nonaqueous electrolyte secondary battery which has excellent corrosion resistance in a battery environment and, when used as a current collector of a nonaqueous electrolyte secondary battery, which enables the nonaqueous electrolyte secondary battery to have excellent cycle characteristics.

A chromium-containing steel sheet for a current collector of a nonaqueous electrolyte secondary battery has a chemical composition containing 10% by mass or more of Cr. The chromium-containing steel sheet has an irregular structure including recesses and protrusions at a surface thereof. The average height of the protrusions is 20 nm or more and 100 nm or less, and the average spacing between the protrusions is 20 nm or more and 300 nm or less.