Metal wire and electric wire
AssigneesYazaki Corporation, The University of Tokyo
InventorsJunichiro Tokutomi, Kenichi Hanazaki, Jun Yanagimoto
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Abstract
To provide a metal wire and an electric wire of high mechanical strength and high ductibility that have sufficiently increased ductibility as well as sufficiently increased mechanical strength. A metal wire manufactured at least by being subjected to an extension in which a metal wire is extended in an axial direction, and having a hardness distribution in which hardness decreases toward a specific peripheral portion from a central portion in a cross-section orthogonal to axis, whereby a softened peripheral portion becomes to show a good malleability as well as a high resistance to cracking, so as to attain an improvement of mechanical strength and ductibility.
Claims7
A metal wire comprising
- a hardness distribution in which hardness decreases toward a specific peripheral portion in a specific radial direction from a central portion in a cross-section orthogonal to an axis,
- wherein the metal wire is manufactured at least by subjecting a metallic material to bending at an approximate right angle in an axial direction with a single feed roller of a bending-stretching mold,
- wherein the bending is subjected only once,
- wherein the bending-stretching mold includes an insertion hole bent at an approximate right angle,
- wherein the single feed roller is arranged inside of a bending portion of the insertion hole and applies a frictional force to an inner circumferential surface of a flexural portion on a circumferential surface of the metallic material at the bending portion,
- wherein the metal wire has a metallographic structure with a grain size equal to or less than 1 μm,
- wherein a hardness distribution of the specific peripheral portion and another hardness distribution of an opposing peripheral portion that opposes to the specific peripheral portion in a radial direction of the metal wire with reference to the central portion are a bilaterally asymmetrical shape with respect to the center portion in the radial direction of the metal wire,
- wherein the hardness of the specific peripheral portion decreases by equal to or more than 10% of that of the central portion at a circumferential surface side being beyond at least ½ of the radius from the center, and
- wherein the another hardness of an opposing peripheral portion falls within plus and minus 10% of that of the central portion, and the another hardness of the opposing peripheral portion is higher than the hardness of the specific peripheral portion.
Dependencies are inferred from the claim text.