The invention provides a steel cord for rubber reinforcement. The steel cord comprises a core strand and at least three outer strands twisted around the core strand, the core strand comprises at least one first core filament and multiple first outer filaments twisted around the first core filament, each outer strand comprises a number of second filaments, at least one of multiple first outer filaments is preformed prior to being twisted into the core strand, and at least one of second steel filaments is straight prior to being twisted to form each outer strand. The steel cord has improved performance on core filament migration.

The subject of the invention is a cord (50) comprising 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.

The subject of the invention is a cord (50) comprising 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.

Pneumatic vehicle tire of radial type of construction, in particular a commercial vehicle tire, having a belt assembly (3) made up of at least three plies (8, 9, 10), namely two working plies (8, 9) and a protective ply (10) arranged radially on the outside with respect to the working plies (8, 9), wherein the protective ply (10) has reinforcing members (11) made up of one or more twisted-together steel filaments (12), wherein the steel of the steel filaments (12) of the reinforcing members (11) of the protective ply (10) can be assigned to the strength class ST or to a higher strength class, wherein the strength class ST has a tensile strength in MPa of 3980-2000 d and the strength class UT has a tensile strength in MPa of 4400-2000 d, wherein d is the diameter of a steel filament in mm.

Pneumatic vehicle tire of radial type of construction, in particular a commercial vehicle tire, having a belt assembly (3) made up of at least three plies (8, 9, 10), namely two working plies (8, 9) and a protective ply (10) arranged radially on the outside with respect to the working plies (8, 9), wherein the protective ply (10) has reinforcing members (11) made up of one or more twisted-together steel filaments (12), wherein the steel of the steel filaments (12) of the reinforcing members (11) of the protective ply (10) can be assigned to the strength class ST or to a higher strength class, wherein the strength class ST has a tensile strength in MPa of 3980-2000 d and the strength class UT has a tensile strength in MPa of 4400-2000 d, wherein d is the diameter of a steel filament in mm.

The invention provides a steel cord for rubber reinforcement. The steel cord comprises a core strand and at least three outer strands twisted around the core strand, the core strand comprises at least one first core filament and multiple first outer filaments twisted around the first core filament, each outer strand comprises a number of second filaments, at least one of multiple first outer filaments is preformed prior to being twisted into the core strand, and at least one of second steel filaments is straight prior to being twisted to form each outer strand. The steel cord has improved performance on core filament migration.

The invention provides a steel cord for rubber reinforcement. The steel cord comprises a core strand and at least three outer strands twisted around the core strand, the core strand comprises at least one first core filament and multiple first outer filaments twisted around the first core filament, each outer strand comprises a number of second filaments, at least one of multiple first outer filaments is preformed prior to being twisted into the core strand, and at least one of second steel filaments is straight prior to being twisted to form each outer strand. The steel cord has improved performance on core filament migration.

A pre-stressed concrete structure comprises a steel wire or a steel strand. The steel wire or steel strand has been pre-tensioned before curing of the concrete or grout. The steel wire or steel strand is provided with a zinc coating. The zinc coating has a weight ranging between 70 g/m.sup.2 and 950 g/m.sup.2. The steel wire or steel strand has an outer surface that is provided with indentions to provide mechanical anchorage points in the concrete structure. The steel wire or steel strand is further provided with a passivation layer in the form of a metal oxide layer.

A pre-stressed concrete structure comprises a steel wire or a steel strand. The steel wire or steel strand has been pre-tensioned before curing of the concrete or grout. The steel wire or steel strand is provided with a zinc coating. The zinc coating has a weight ranging between 70 g/m.sup.2 and 950 g/m.sup.2. The steel wire or steel strand has an outer surface that is provided with indentions to provide mechanical anchorage points in the concrete structure. The steel wire or steel strand is further provided with a passivation layer in the form of a metal oxide layer.

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.