The disclosure aims to provide a structural member made of an extruded material that effectively helps to reduce weight while ensuring strength and rigidity. The structural member has a varied wall thickness along an extrusion direction.

A steel product bent by heating to 600 C. or more, specifically a heat treated steel product having high strength and excellent chemical conversion coating ability which has scale with FeO content of 90% or more, having a thickness of 1 m or less on the surface.

Surface treated copper foils for use in high speed circuits on the order of 100 MHz or greater contain a reverse treated layer of copper nodules on the drum side of the electrolytically deposited copper foil to form a lamination side to be laminated to a dielectric material to form a copper clad laminate. Methods of forming the surface treated copper foil, and printed circuit boards (PCB) from the copper clad laminates are also described. The surface treated copper foils, copper clad laminates and PCBs can be incorporated into various electronic devices in which high speed signals are employed, including personal computers, mobile communications, including cellular telephones and wearables, self-driving vehicles, including cars and trucks, and aviation devices, including manned and unmanned vehicles, including airplanes, drones, missiles and space equipment including satellites, spacecraft, space stations and extra-terrestrial habitats and vehicles.

A carrier-attached copper foil having good circuit formability is provided. The carrier-attached copper foil has a carrier, an intermediate layer and an ultra-thin copper layer in this order, the average grain size of crystal grains that form the ultra-thin copper layer is 1.05 to 6.5 m, and a ten point average roughness Rz of a surface on a side of the ultra-thin copper layer is 0.1 to 2.0 m.

A curved, three-dimensional, ordered micro-truss structure including a series of first struts extending along a first direction, a series of second struts extending along a second direction, and a series of third struts extending along a third direction. The first, second, and third struts interpenetrate one another at a series of nodes. The series of first struts, second struts, third struts, and nodes form a series of ordered unit cells within the micro-truss structure. The series of ordered unit cells define a curved surface.

There is provided a roughened copper foil which can significantly improve adhesion to an insulating resin and reliability (e.g., hygroscopic heat resistance). The roughened copper foil of the present invention has at least one roughened surface having fine irregularities composed of acicular crystals, wherein the entire surface of the acicular crystals is composed of a mixed phase of Cu metal and Cu.sub.2O.

A workpiece includes a plurality of knots and webs, which are formed in one piece, of a sheet metal, in particular a steel plate. Each web extends between two openings from one knot to another knot, and at least three webs meet at each knot. A plurality of the webs has a cross section, which includes at least one hardened and one unhardened area.

A workpiece includes a plurality of knots and webs, which are formed in one piece, of a sheet metal, in particular a steel plate. Each web extends between two openings from one knot to another knot, and at least three webs meet at each knot. A plurality of the webs has a cross section, which includes at least one hardened and one unhardened area.

A carrier-attached copper foil having good circuit formability is provided. The carrier-attached copper foil has a carrier, an intermediate layer and an ultra-thin copper layer in this order, the number of crystal grains per unit cross-sectional area of the ultra-thin copper layer in the through-thickness direction is 0.1 to 5 grains/m.sup.2, and a ten point average roughness Rz of a surface on a side of the ultra-thin copper layer is 0.1 to 2.0 m.

A hollow shaft includes a cylindrical main body part and an extremity drawn part that is integrally connected to one end of the main body part on the same axis and whose diameter is made smaller than a diameter of the main body part by drawing processing, wherein an inner peripheral face of the main body part and an inner peripheral face of a base portion, which is continuous with one end side of the main body part, of the extremity drawn part are formed as cut faces that are subjected to cutting processing before the drawing processing, and an inner peripheral face of a tip portion, which is continuous with an extremity side of the base portion, of the extremity drawn part is a non-cut face. Accordingly, the hollow shaft can be molded with high shape precision while maintaining a low drawing ratio for an extremity drawn part.