Stranding with the same direction of lay for all layers.

A number of bunches twisted together so that each bunch, with the exception of the center one, has a helical form of predetermined lay ratio. Alternate layers are usually stranded in opposite directions.

A conductor composed of individual groups of wires twisted together to form an entire unit. A number of wires are twisted together, usually built up on a single central conduc­tor with 6 wires in a first layer, 12 in a second, 18 in a third and so on. Most con­ductors therefore have 7, 19, 37, 61 or 91 wires. When there is more than one layer in a stranded conductor, the direction of lay is reversed in adjacent layers.

A weave in which both warp and weft consist of several wires twisted together instead of single wires. This provides an exceptionally strong cloth especially when twill woven. An even tighter weave is obtained when the cloth is rolled or calendared. In stranded warp weave, the warp consists of several wires twisted together while the weft is of single wires. See Weaving Wire and Woven Wire Mesh.

A type of machine that twists a number of individual strands of wire and forms them as they go through a tightly fitting die into a group, some of which may, in turn, be twisted into larger groups. This is similar to the function of a buncher, the difference being that a strander is configured so that the spools holding the wire to be stranded are located within the rotating element of the machine, with the product taken up outside the machine, whereas a buncher has the supply spools on the outside and the product is taken up inside the rotating element of the machine. See individual entries.

This machine is similar to a tubular strander, the difference being the rotating tube or barrel is replaced with a rotating bow, which reduces the rotating mass and permits higher speeds.

A wire rope stranding machine in which the multiple of individual spools of wire are supported in cradles suspended in a rotating carriage. This allows the formation of a strand in which the individual components are free of residual torsional forces. The cradles operate with planetary motion derived from sun and planet gearing located at one end of the rotating carriage. The wires are led from the spools through the front trunnion of the supporting cradles to the lay plate, forming die and then to the capstan haul-off and take-up drum.

An alternative name for a tubular strander, in which the stranding bobbins are mounted in floating frames along the centerline of a large rotating tube.

A high speed stranding machine in which the multiple stranding bobbins are mounted in floating frames along the center line of a large rotating steel tube which is cut away at intervals so that the bobbins can be inserted. The wires pass along the internal or external periphery of the tube to the end of the machine. A core wire is passed through the center of the end of the machine and all wires are threaded through the closing die. The stranded wire is pulled out of the tubular by a dual or single wheel capstan and then onto a spooler.

Twisting of a plurality of wires (from 3 to 168 or potentially more) into a geometrically consistent finished strand. A typical example is the classical 1+6+12 strand where each strand component will always be located in the same geometric position throughout the strand length. A number of stranding machines may be coupled together. For example, in a triple tandem strander for 37-wire strand, the first machine spins six wires around a core wire. This strand is led through the center of a 12-bobbin machine, making 19 wires. It then forms a 37-wire strand upon being led forward again through an 18-bobbin machine. Note: stranding is different from bunching, where the plurality of wires are twisted into a random formation. Also, one of the purposes for stranding is to provide flexibility.

A solid reduction die or a pair of steel blocks, which when put together in a die holder, form a circular or sector shaped hole through which the stranded wires pass to form the finished strand.

A ratio of the mass or electrical resistance of a unit length of a stranded conductor to that of a solid conductor of an equivalent cross-sectional area.

See Strand, Unidirectional.

See Strand, Unilay.

Square- or rectangular-section bare conductor manufactured and used in coil form.

Force or load per unit area, often thought of as force acting through a small area within a plane. Can be divided into normal, perpendicular to the surface, and shear, parallel to the surface, components. The stresses in wire products are often calculated by dividing the axial load on the wire by its cross-sectional area.

Cracking due to the combined effects of stress and corrosion. The stress can be either internal (residual) or external (applied). Usually this type of failure occurs as a fine hairline crack that propagates across the section without any exterior sign of corrosion.

Heating and coolingto low temperatures to homogenize stresses so as to afford the best possible combination of ductility and strength. For metal alloys this partial recovery process increases yield strength significantly, with slight increases in tensile strength and hardness, but little change in percent elongation. Stress equalizing, which is often applied to coil springs and wire forms in their finished shape, is a common practice in many wire-manufacturing operations.

1) In a spring, the difference between the stresses induced by the maximum and minimum applied loads in a component subjected to cyclic loading. 2) In fatigue, the difference between the maximum and minimum stress in one cycle of repetitively varying stress.

A process of reducing residual stresses in a metal object by heating the a metal object to a suitable temperature below annealing or transition temperatures, and holding for a sufficient time, usually followed by slow cooling. This treatment may be applied to relieve stresses induced by casting, quenching, normalizing, machining, cold working or welding. Steel wire makers may relieve stresses created in the wiredrawing process to increase the final tensile strength and preventing stress corrosion.