Provided is a thin, narrow tube for use in a biodegradable medical device formed from a round tube made of a magnesium material as the base material, in which a desired outer diameter and an inner diameter are provided with good precision over the entire region in a longitudinal direction and a circumferential direction, and the length of biodegradation time can be controlled without changing a material composition. The thin, narrow tube is a thin, narrow tube of a biodegradable medical device, in which the thin, narrow tube is a round tube made of crystals containing magnesium (Mg) having a hexagonal crystal structure, and when the crystals forming the round tube are viewed in a round tube axis direction of the round tube, a hexagonal basal plane (0001) is oriented at a predetermined inclination angle with respect to a circumferential direction perpendicular to a radial direction (a direction from an inner surface to an outer surface) of the round tube.

A forging tool is to forge a workpiece in a cuboidal forging space, and wherein (a): the forging space is formed when the bottom surface of the first die and the bottom surface of the second die are brought into contact with the contact surface of the third die, or (b): the forging space is formed when a first die contact surface provided in the first die and a second die contact surface provided in the second die are brought into contact with each other.

A sprocket wheel, which is a machine component configured to slide relative to a bushing while being in contact with the bushing in an outer peripheral surface, includes a base made of a first metal, and an overlay that covers the base so as to constitute the outer peripheral surface. The surface of the overlay constituting the outer peripheral surface has been smoothed. Such a smoothed surface of the overlay makes the sprocket wheel less damaging to the bushing.

A steel part includes a steel sheet substrate and a coating on at least one surface of the steel sheet 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 steel sheet substrate and the coating have at least one deformation. An outer surface of the coating has a waviness Wa.sub.0.8 of less than or equal to 0.43 m.

A peening method which can sufficiently improve fatigue properties of a lap fillet welded joint having a thin steel sheet as a base sheet, in which a knocking pin having a predetermined shape is continuously knocked as a series of knocking toward a direction inclined relative to the welding direction, the series of knocking is repeatedly performed in the welding direction, at that time, a knocking mark group made of a plurality of knocking marks formed by the series of knocking is superimposed on at least a part of an adjacent knocking mark group while an end part in the direction orthogonal to the welding direction of the knocking mark group is separated from an end part in the direction orthogonal to the welding direction of the adjacent knocking mark group.

The present invention provides a method for manufacturing a metal sheet. In this method, at least one of the following equations is satisfied: $\begin{array}{cc}\frac{Z}{d}+18\ln \left(\frac{Z}{d}\right)<8\ln \left(\frac{P}{V}\right)-27.52& \left(A\right)\\ f{O}_2<\frac{2.304.Math.{10}^{-3}}{{(27.52+\frac{Z}{d}+8\ln (}^{}}\end{array}$

A flat steel product for hot forming may be produced from a steel substrate that includes a steel comprising 0.1-3% by weight Mn and up to 0.01% by weight B, along with a protective coating that is applied to the steel substrate. The protective coating may be based on Al and may contain up to 20% by weight of other alloy elements. Also disclosed are methods for producing such flat steel products, steel components, and methods for producing steel components. Absorption of hydrogen is minimized during heating necessary for hot forming. This is achieved at least in part through an alloy constituent of 0.1-0.5% by weight of at least one alkaline earth or transition metal in the protective coating, wherein an oxide of the alkaline earth or transition metal is formed on an outer surface of the protective coating during hot forming of the flat steel product.

A flat steel product for hot forming may be produced from a steel substrate that includes a steel comprising 0.1-3% by weight Mn and up to 0.01% by weight B, along with a protective coating that is applied to the steel substrate. The protective coating may be based on Al and may contain up to 20% by weight of other alloy elements. Also disclosed are methods for producing such flat steel products, steel components, and methods for producing steel components. Absorption of hydrogen is minimized during heating necessary for hot forming. This is achieved at least in part through an alloy constituent of 0.1-0.5% by weight of at least one alkaline earth or transition metal in the protective coating, wherein an oxide of the alkaline earth or transition metal is formed on an outer surface of the protective coating during hot forming of the flat steel product.

A chassis component for a motor vehicle is disclosed. The chassis component (1) is manufactured at least partially from a multi-layer steel sheet (10, 20, 30). The multi-layer steel sheet (10, 20, 30) includes at least three steel layers, including two outer steel layers (11, 12; 21, 22; 31, 32) and one inner steel layer (13, 23, 33). At least one outer steel layer (11, 12; 21, 22; 31, 32) of the multi-layer steel sheet (10, 20, 30) has a tensile strength of at least 1200 MPa. A method for producing a chassis component for a motor vehicle, in particular a wheel (1) or a part thereof, is also disclosed.

A chassis component for a motor vehicle is disclosed. The chassis component (1) is manufactured at least partially from a multi-layer steel sheet (10, 20, 30). The multi-layer steel sheet (10, 20, 30) includes at least three steel layers, including two outer steel layers (11, 12; 21, 22; 31, 32) and one inner steel layer (13, 23, 33). At least one outer steel layer (11, 12; 21, 22; 31, 32) of the multi-layer steel sheet (10, 20, 30) has a tensile strength of at least 1200 MPa. A method for producing a chassis component for a motor vehicle, in particular a wheel (1) or a part thereof, is also disclosed.