The invention relates to a brake piston 1 for a brake caliper 9 of a disk brake, which is produced using working processes from a metallic material, in particular from a flat metal sheet, and is formed in one piece as a unilaterally open pot with a piston longitudinal axis A, with a piston wall 2 and with a piston head 3. There is a need for robust and light as well as alternatively constructed, efficiently producible and well guided brake pistons. The object is achieved firstly in principle on the basis of a cup-shapedly worked brake piston blank 19, in that at least one locally defined, i.e. partially cold-upset or partially ironed, cylindrical piston wall portion is present with a partially deformed piston wall 2 which is configured in adaptively modified manner by plastic material deformation by means of material redistribution (flow) including strain-hardening of its piston wall thickness of sl−x.

A process for cold working of the inner surface of a bore in a centrifugal compressor wheel along only a fractional portion of the bore length (i.e., along less than a full axial length of the bore), thereby creating a zone of compressive residual hoop stress in the metal surrounding the bore where the wheel needs the beneficial residual stress. The process purposefully avoids cold working of the bore at locations adjacent to high-stress areas and features of the wheel, where cold working in such locations could negatively impact the wheel's overall life.

A coated metal sheet includes a steel substrate and a coating on at least one surface of the steel substrate. The coating includes between 0.2 and 0.7% by weight of Al, with a remainder of the metal coating being Zn and inevitable impurities. The coated metal sheet was subjected to a skin pass operation after coating. An outer surface of the metal coating has a waviness Wa.sub.0.8 of less than or equal to 0.55 μm.

A coated metal sheet includes a steel substrate and a coating on at least one surface of the steel substrate. The coating includes between 0.2 and 0.7% by weight of Al, with a remainder of the metal coating being Zn and inevitable impurities. The coated metal sheet was subjected to a skin pass operation after coating. An outer surface of the metal coating has a waviness Wa.sub.0.8 of less than or equal to 0.55 μm.

The present invention relates to the technical field of material processing and provides a method for making a metal material composite, including: contacting a first surface of a first plate with a second surface of a second plate; placing the first plate and the second plate in a recess in a circumferential direction of a first roller such that a third surface of the second plate contacts a bottom wall of the recess in a circumferential, the third surface being opposite the second surface, the first plate having a greater hardness than the second plate; and controlling a first roller and a second roller to rotate, thereby rolling to combine the first plate and the second plate into a composite plate, where a fourth surface of the first plate contacts a surface of the second roller and the fourth surface is opposite the first surface during the rolling. According to the method for making a metal material composite in the present invention, flashings and burr on the side edges of a composite plate are avoided by placing the first plate and the second plate in a recess for machining.

Disclosed are a ferrite-based stainless steel having improved surface characteristics and a method for manufacturing same. The ferrite-based stainless steel according to the present invention includes, in percent by weight (wt %), 0.001 to 0.05% of C, 0.001 to 0.05% of N, 0.1 to 1.0% of Si, 0.1 to 1.0% of Mn, 12.0 to 22.0% of Cr, 0.01 to 1.0% of Ti, 0.01 to 1.0% of Nb, and the remainder of Fe and unavoidable impurities, wherein micro flaws having a length of 100 μm or more are distributed at a density of 5 pieces/mm.sup.2 or less.

A processing method according to one aspect incudes preparing a metal workpiece having a hole that opens to a surface thereof, filling the hole with processing media, and applying an external force to the processing media to apply a compressive residual stress to an inner surface of the hole.

The invention relates to a steel sheet skin-pass rolled with a deterministic surface structure, and to a method for producing it.

Methods of strengthening surface regions of high-strength transformation induced plasticity (TRIP) steel are provided. The method may comprise shot peening at least one region of an exposed surface of a hot-formed press-hardened component comprising a high-strength steel. Prior to shot peening, the component has a microstructure comprising ≧about 5% by volume retained austenite in a matrix of martensite. The shot peening is conducted at a temperature of <about 150° C. and forms at least one hardened surface region comprising ≦about 2% by volume austenite. The TRIP steel may be zinc-coated and having a surface coating comprising zinc and substantially free of liquid metal embrittlement (LME). Zinc-coated hot-formed press-hardened components, including automotive components, formed from such methods are also provided.

A method and apparatus for improving the fatigue and stress corrosion cracking performance of irregular surfaces, such as welds assemblies of components, using a positioning system, such as a robotic or CNC machine, to position a tool head for inducing compression along and into the surface of a workpiece to automatically follow the surface irregularities. The method and apparatus operates to follow a virtual control surface located below the actual surface of the workpiece thereby allowing the irregular topography surface to be uniformly processed with closed loop process control.