A steel sheet according to an aspect of the present invention has a predetermined chemical composition, in which a steel structure of an inside of the steel sheet contains, by volume fraction, soft ferrite: 0% to 30%, retained austenite: 3% to 40%, fresh martensite: 0% to 30%, a sum of pearlite and cementite: 0% to 10%, and a remainder including hard ferrite, in the inside of the steel sheet, a number proportion of the retained austenite having an aspect ratio of 2.0 or more in the total retained austenite is 50% or more, a soft layer having a thickness of 1 μm to 100 μm from the surface is present in a sheet thickness direction, among ferrite contained in the soft layer, a volume fraction of grains having an aspect ratio of less than 3.0 is 50% or more, a volume fraction of retained austenite in the soft layer is 50% or more of the volume fraction of the retained austenite of the inside of the steel sheet, and a peak of an emission intensity at a wavelength indicating Si appears in a range of more than 0.2 μm from the surface to 5 μm or less from the surface.

A component made of metallic composite material having high corrosion resistance and scale resistance. The metallic composite material contains as a core material an uncoated hardenable steel on which surface a corrosion resistance and scaling resistance layer is provided using heat resistant stainless steel, and has a yield strength Rp.sub.0,2 of at least 1000 MPa and a tensile strength R.sub.m of at least 1500 MPa for the core material and a critical scaling resistance temperature in air for the layer material is at least 850° C.

A welded member includes a hot dip Zn-based alloy coated steel sheet as a base material and has excellent corrosion resistance and weld bead shear strength. In the welded member in which a lower sheet and an upper sheet, which are hot dip Zn-based alloy coated steel sheets, are stacked and arc-welded together, a weld bead is formed so that a cross-sectional width W satisfies the following formula 2T≤W≤6T, and a blowhole occupancy Br represented by the following formula becomes not more than 50%: Br=(Σdi/L)×100, where T represents a thickness of the hot dip Zn-based alloy coated steel sheet, di represents a length of an i-th blowhole observed in X-ray radiography, and L represents a length of the weld bead.

A method for manufacturing a copper foil with a rough surface in a plating tank includes causing an electrolyte solution to flow between an anode and a cathode with a current density of 5 ASF-40 ASF. The copper foil with a rough surface including dense nodules of single copper crystals is deposited on the cathode. The electrolyte solution includes chloride ions (20 ppm-80 ppm), polyethylene glycol (PEG) with a molecular weight of 400-8000 (100 ppm-700 ppm), sulfuric acid (20 g/L-200 g/L), copper sulfate pentahydrate (70 g/L-320 g/L) and a sulfur compound (1 ppm-60 ppm).

A surface-treated steel sheet for a battery container, including a steel sheet, an iron-nickel diffusion layer formed on the steel sheet, and a nickel layer formed on the iron-nickel diffusion layer and constituting the outermost layer, wherein when the Fe intensity and the Ni intensity are continuously measured from the surface of the surface-treated steel sheet for a battery container along the depth direction with a high frequency glow discharge optical emission spectrometric analyzer, the thickness of the iron-nickel diffusion layer being the difference between the depth at which the Fe intensity exhibits a first predetermined value and the depth at which the Ni intensity exhibits a second predetermined value is 0.04 to 0.31 m; and the total amount of the nickel contained in the iron-nickel diffusion layer and the nickel contained in the nickel layer is 10.8 to 26.7 g/m.sup.2.

An aluminium-zinc-hot-dipped and colour-coated steel plate having a 600 MPa yield strength grade and a high elongation and a manufacturing method thereof, with the chemical components in mass percentage of a substrate of the steel plate being: 0.07-0.15% of C, 0.02-0.5% of Si, 1.3-1.8% of Mn, N0.004%, S0.01%, Ti0.20%, Nb0.060%, and the balance being Fe and other inevitable impurities, and meanwhile satisfying the conditions of: (C+Mn/6)0.3%; Mn/S150; Nb satisfying 0.01%(Nb0.22C1.1N)0.06% where no Ti is contained; Ti satisfying 0.5Ti/C1.5 where no Nb is contained; and 0.04%(Ti+Nb)0.26% where Ti and Nb are added in combination. The steel plate has a yield strength of 600 MPa, a tensile strength of 650 MPa, an elongation after fracture of 12%, a good strength and toughness and an excellent corrosion resistance.

An example hydraulic system component of a machine includes a protective coating deposited by high velocity air fuel (HVAF) thermal spray, exhibiting high adhesion strengths and surface morphologies that promote lubricant adhesion and reduce the leakage of oil and/or hydraulic fluid from the hydraulic system. The coating may have surface roughness with R.sub.Z values less than 2 m and hardness of 1000 Vickers or greater. The HVAF coating may be thinner than conventional coatings with thicknesses less than 100 m. The HVAF coating may be deposited on a variety of steel components with adhesion strengths greater than those achieved by high velocity oxygen fuel (HVOF). The HVAF coating may be formed without time consuming roughening and/or post-grind operations, resulting in cost savings compared to conventional coatings. The coatings may have operational lifetimes of 1000 hours or more.

The present invention provides a nickel-plated heat-treated steel sheet for a battery can (1), having a nickel layer with a nickel amount of 4.4 to 26.7 g/m.sup.2 on a steel sheet (11), wherein when the Fe intensity and the Ni intensity are continuously measured along the depth direction from the surface of the nickel-plated heat-treated steel sheet for a battery can, by using a high frequency glow discharge optical emission spectrometric analyzer, the difference (D2-D1) between the depth (D1) at which the Fe intensity exhibits a first predetermined value and the depth (D2) at which the Ni intensity exhibits a second predetermined value is less than 0.04 m.

A metallic structure includes a first plurality of metal particles arranged in an amorphous structure; a second plurality of metal particles arranged in a crystalline structure having at least two grain sizes, wherein the crystalline structure is arranged to receive the amorphous structure deposited thereon; wherein the grain size is arranged in a gradient structure.

A titanium member includes a first region where a plurality of first convex structural bodies extending in a first direction are arranged on the surface of the titanium member in a second direction orthogonal to the first direction, the first convex structural body has first convex portions arranged on an upper surface of the first convex structural body at an interval of several hundred nanometers along the first direction, and a height of the first convex portion is several ten nanometers. It is preferable that the first convex structural bodies adjacent in the second direction are arranged at an interval wider than the interval at which the first convex portions are arranged, and in the first convex structural bodies, a height including the first convex portion is higher than the height of the first convex portion.