Provided is a steel cord for rubber article reinforcement which has excellent corrosion resistance and productivity without deterioration of adhesion with rubber. A steel cord (1) for rubber article reinforcement, in which plural steel filaments (2) are twisted together, includes: a core having at least one core filament (2c); and a sheath having at least one sheath layer formed by twisting at least one sheath filament (2s) around the core. In this steel cord (1), brass plating is performed on the steel filaments (2) and zinc plating is further performed on the outer circumference of the brass plating of the core filament (2c), and the steel filaments (2) have a diameter d of 0.1 mm to 0.6 mm.

A method for stranding aramid yarn around an endless core includes a stranding step that involves a stranding apparatus having at least one yarn bobbin. The bobbin revolves around its own axis and the bobbin revolves around the core, wherein the yarn unwinds from the bobbin and winds around the core. The yarn is a continuous aramid yarn provided with 0.05 to 0.95 wt %, based on the weight of the aramid, of a finish including an organophosphorus compound. The organophosphorus compound is a compound of the formula X1X2X3P═O. X1, X2, and X3 are independently selected from Y1-, Y1-O—, and M-O. Y1 is a branched or straight-chain C1-C20 alkyl, aryl or alkenyl. M is selected from Li, Na, K, or ammonium. At least one of X1, X2, or X3 is selected from Y1- or Y1-O—.

A method for stranding aramid yarn around an endless core includes a stranding step that involves a stranding apparatus having at least one yarn bobbin. The bobbin revolves around its own axis and the bobbin revolves around the core, wherein the yarn unwinds from the bobbin and winds around the core. The yarn is a continuous aramid yarn provided with 0.05 to 0.95 wt %, based on the weight of the aramid, of a finish including an organophosphorus compound. The organophosphorus compound is a compound of the formula X1X2X3P═O. X1, X2, and X3 are independently selected from Y1-, Y1-O—, and M-O. Y1 is a branched or straight-chain C1-C20 alkyl, aryl or alkenyl. M is selected from Li, Na, K, or ammonium. At least one of X1, X2, or X3 is selected from Y1- or Y1-O—.

A steel wire rope is presented for use in elevators and lifting applications. The steel wire rope contains a core surrounded by multiple strands. The outer filaments of the core and the outer filaments of the strands are likely to contact one another during used. The outer steel filaments of the core have an average Vickers hardness that is at least 50 Vickers hardness numbers lower than that of the outer filaments of the strands. As the hardness of the outer filaments of the core is substantially lower than that of the outer filaments of the strands, those softer filaments will preferentially abrade away during use. In this way the core is sacrificed while preserving the integrity of the outer filaments of the strands. The use of this ‘sacrificial core’ results in a higher residual breaking load after use.

A steel wire rope is presented for use in elevators and lifting applications. The steel wire rope contains a core surrounded by multiple strands. The outer filaments of the core and the outer filaments of the strands are likely to contact one another during used. The outer steel filaments of the core have an average Vickers hardness that is at least 50 Vickers hardness numbers lower than that of the outer filaments of the strands. As the hardness of the outer filaments of the core is substantially lower than that of the outer filaments of the strands, those softer filaments will preferentially abrade away during use. In this way the core is sacrificed while preserving the integrity of the outer filaments of the strands. The use of this ‘sacrificial core’ results in a higher residual breaking load after use.

Rubber article-reinforcing steel cord in which corrosion resistance is improved without an increase in weight. In a rubber article-reinforcing steel cord (1), plural sheath strands (3) each formed by twisting together plural steel filaments are twisted together around at least one core strand (2) formed by twisting together plural steel filaments. Core strand (2) and sheath strands (3) are each formed by twisting together one or two core filaments (2c) and (3c) and plural sheath filaments (2s) and (3s), respectively, and a relationship represented by the following Formula (1) is satisfied when a wire diameter of core filament(s) (2c) of core strand (2), a wire diameter of sheath filaments (2s), a wire diameter of core filaments (3c) of sheath strands (3), and a wire diameter of sheath filaments (3s) are defined as dcc, dcs, dsc and dss, respectively: dcc>dcs≥dsc>dss (1).

Rubber article-reinforcing steel cord in which corrosion resistance is improved without an increase in weight. In a rubber article-reinforcing steel cord (1), plural sheath strands (3) each formed by twisting together plural steel filaments are twisted together around at least one core strand (2) formed by twisting together plural steel filaments. Core strand (2) and sheath strands (3) are each formed by twisting together one or two core filaments (2c) and (3c) and plural sheath filaments (2s) and (3s), respectively, and a relationship represented by the following Formula (1) is satisfied when a wire diameter of core filament(s) (2c) of core strand (2), a wire diameter of sheath filaments (2s), a wire diameter of core filaments (3c) of sheath strands (3), and a wire diameter of sheath filaments (3s) are defined as dcc, dcs, dsc and dss, respectively: dcc>dcs≥dsc>dss (1).

A steel cord containing a core layer and an sheath layer, the core layer containing a plurality of core wires with a number of n and the sheath layer comprises a plurality of sheath wires with a number of m, and the steel cord has a flat cross-section with a major axis and a minor axis, the flat cross-section has a flat ratio being the ratio of the length of the major axis and the length of the minor axis, the flat ratio is more than 1.2, the steel cord has a breaking load being BL.sub.cord, the core wires and the sheath wires have a sum breaking load being Sum BL.sub.wires when the core wires and the sheath wires are un-twisted from the steel cord, BL.sub.cord and Sum BL.sub.wires satisfies the following formula: BL.sub.cord/Sum BL.sub.wires>96%. The steel cord has higher breaking load.

A steel cord containing a core layer and an sheath layer, the core layer containing a plurality of core wires with a number of n and the sheath layer comprises a plurality of sheath wires with a number of m, and the steel cord has a flat cross-section with a major axis and a minor axis, the flat cross-section has a flat ratio being the ratio of the length of the major axis and the length of the minor axis, the flat ratio is more than 1.2, the steel cord has a breaking load being BL.sub.cord, the core wires and the sheath wires have a sum breaking load being Sum BL.sub.wires when the core wires and the sheath wires are un-twisted from the steel cord, BL.sub.cord and Sum BL.sub.wires satisfies the following formula: BL.sub.cord/Sum BL.sub.wires>96%. The steel cord has higher breaking load.

A cord (50) comprises a single layer (52) of helically wound metal filamentary elements (54). The metal filamentary elements define an internal enclosure (58) of the cord of diameter Dv. Each metal filamentary element (54) has a diameter Df and a helix radius of curvature Rf. With Dv, Df and Rf being expressed in millimetres, the cord satisfies the following relationships: 9≤Rf/Df≤30 and 1.30≤Dv/Df≤2.10.