A steel filament for twisting into a steel cord for the reinforcement of rubber articles, which contains a steel substrate that is coated with a coating comprising brass. The coating is different in that the amount of iron at the surface is distinctively higher than that prior steel filaments. The coating has an average iron content of 4 or more atomic percent compared to the total of iron, zinc and copper atoms in the layer extending from the surface to a depth of 3 nanometer below the surface. The steel filaments show an improved adhesion retention under hot and humid conditions and in organic cobalt compound containing rubbers as well as rubbers that are substantially free of cobalt. The lifetime of the rubber article is extended.

A multi-strand cord (50) comprises an internal layer (CI) made up of K=1 internal strand (TI) having two layers (C1, C3), with the internal layer (C1) being made up of Q internal metallic threads (F1) and the external layer (C3) being made up of N external metallic threads (F3), and an external layer (CE) made up of L>1 external strands (TE) having two layers (C1′, C3′) wound around the internal layer (CI), with the internal layer (C1′) being made up of Q′ internal metallic threads (F1′) and the external layer (C3′) being made up of N′ external metallic threads (F3′). The cord (50) has an energy-to-break per unit area ES≥145 N.Math.mm.sup.−1 with ES=Σ.sub.i=1.sup.NcF.sub.mi×Σ.sub.i=1.sup.NcA.sub.ti/Nc×Cfrag/D where Σ.sub.i=1.sup.NcF.sub.mi is the sum of the forces at break, Σ.sub.i=1.sup.NcA.sub.ti is the sum of the total elongation, Cfrag is the coefficient of weakening, and D is the diameter.

Provided are a rubber article reinforcing steel wire that is superior in bending fatigue properties to the related art and has a flat cross-sectional shape, and a rubber article using the wire. In a rubber article reinforcing steel wire 10, a major diameter and a minor diameter are substantially perpendicular to each other. Assuming that the major diameter is W, the minor diameter is T, a straight line that passes through a center of the major diameter in a width direction and is parallel to a minor diameter direction is L1, a straight line that passes through a center of the minor diameter in a width direction and is parallel to a major diameter direction is L2, an intersection point of the L1 and the L2 is a center point C, a region within a half of a distance from the center point C to a surface is a central region Rc, and a region outside the central region Rc is a surface layer region Rs, a Vickers hardness Hvc of the central region Rc is more than a Vickers hardness Hvs of the surface layer region Rs; and assuming that a Vickers hardness on the L1 in the surface layer region Rs is Hv1, and a Vickers hardness on the L2 in the surface layer region Rs is Hv2, relationships represented by Hvc−Hv1≦150, Hvc−Hv2≦150, Hv1/Hvc×100≧85.11, and Hv2/Hvc×100≧79.84 are satisfied.

A wire rope having improved durability and that can be used in a medical device to be inserted into a patient's body. The wire rope includes a core wire and side wires. The core wire is a special metal element wire that has a hardness at an outer periphery in a cross-section thereof that is higher than that at a center in the cross-section thereof. The wire rope does not include grease.

The steel wire for the steel cord of the present invention includes a plating layer of Cu-M-Zn (M is one or two elements of Co, Ni, Cr, Mo, Al, In, or Sn) and has a concentration gradient in which the M content ratio in a region from the surface to ¼ of the plating layer is 40% or more compared with the M content ratio in the entire region of the plating layer, and the steel cord for rubber reinforcement is obtained by a manufacturing method comprising: performing sequential plating on a surface of a steel wire in the order of Cu.fwdarw.M.fwdarw.Zn; performing a primary diffusion, for concentration gradient of M, by subjecting the sequentially plated steel wire to high-frequency induction heating using 1-500 MHz; and performing a secondary diffusion, following the primary diffusion, by medium-frequency induction heating using 10-500 KHz.

The present invention relates to a steel cord for rubber reinforcement wherein a steel wire for steel cord has a plating layer of a ternary or quaternary alloy.

The steel wire for the steel cord of the present invention comprises a plating layer of Cu-M-Zn (M is one or two elements of Co, Ni, Cr, Mo, Al, In, or Sn) and has a concentration gradient in which the M content ratio in a region from the surface to ¼ of the plating layer is 40% or more compared with the M content ratio in the entire region of the plating layer, and the steel cord for rubber reinforcement is obtained by a manufacturing method comprising: performing sequential plating on a surface of a steel wire in the order of Cu.fwdarw.M.fwdarw.Zn; performing a primary diffusion, for concentration gradient of M, by subjecting the sequentially plated steel wire to high-frequency induction heating using 1-500 MHz; and performing a secondary diffusion, following the primary diffusion, by medium-frequency induction heating using 10-500 KHz.

A tungsten wire according one aspect of the present disclosure includes: a metal wire containing one of tungsten and a tungsten alloy; and a plating layer which covers a surface of the metal wire. The plating layer contains copper.

Provided are a high-strength bead wire and a method of manufacturing the same. The method includes preparing a wire rod containing 0.86% to 1.02% by weight of carbon, applying 5 g/m.sup.2 to 10 g/m.sup.2 of phosphate coating onto the surface of the wire rod, and drawing the wire rod onto which the phosphate coating is applied. In the drawing, the wire rod is drawn by a drawing apparatus including a drawing die capable of drawing the wire rod and a pressure die installed in front of the drawing die and capable of applying pressure to the wire rod. The diameter of the pressure die is 1.05 times to 1.20 times the diameter of the drawing die. The high-strength bead wire includes a wire rod containing 0.86% to 1.02% by weight of carbon and 5 g/m.sup.2 to 10 g/m.sup.2 of the phosphate coating applied onto the surface of the wire rod and is manufactured by the above-described method.

Chemical compositions of a tire cord steel with high strength and low wire breakage rate may include Nb, V and N, and ([Nb]+[V])/[N] is 3-4.5, [Nb] representing the mass fraction of niobium element, [V] representing the mass fraction of vanadium element, and [N] representing the mass fraction of nitrogen element. The method includes: obtaining a steel billet of the tire cord steel; and sequentially performing a heating-before-rolling, a hot-rolling and a cooling-after-rolling on the steel billet to obtain a wire rod of the tire cord steel. The application of the tire cord steel is to apply the tire cord steel in tire skeleton materials. The strength and toughness of the tire cord steel can be improved by adding Nb, V and N, and then controlling the relationship between Nb, V and N.

A tire includes a steel cord having a plated coating layer, rubber covering the steel cord, the plated coating layer including Cu and Zn, and a bonding layer including Cu.sub.2S and CuS provided closer to the rubber than an interface between the steel cord and the rubber, wherein a molar ratio Cu.sub.2S/CuS of Cu.sub.2S and CuS included in the bonding layer is 1.0 or higher.