JPH0139165B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the manufacture of steel-core aluminum stranded wires (hereinafter referred to as ACSR wires), which are made by twisting aluminum or aluminum alloy wires (hereinafter referred to as aluminum wires) around the outer periphery of a steel core. In particular, the present invention relates to a method for producing an ACSR wire in which a steel core of aluminum strands is permanently strained to increase the strength of the stranded wire.

BACKGROUND OF THE INVENTION Conventional ACSR wires generally include, for example, a galvanized steel wire 1 with aluminum wires 2 twisted around the outer periphery, as shown in FIG. The tensile strength of such a stranded wire is calculated by considering the non-uniformity of stress in each layer due to alternate twisting and the load sharing between the aluminum wire and steel wire, with respect to the sum of the tensile strengths of the aluminum wire and steel wire. However, in practice, there is a large difference in elongation at break between aluminum wire and steel wire, so the value is lower than the sum of the tensile strengths of aluminum wire and steel wire, and the tensile strength of each wire cannot be sufficiently increased. I can't say that I use it.

In other words, in ACSR wire, the elongation at break of aluminum wire and steel wire are significantly different, approximately 2 to 4% and 5 to 7%, respectively. Even if the effect of alternate twisting is considered, the aluminum wire will break at a tensile load lower than the sum of the tensile strengths of each wire. Ideally, the aluminum wire and the steel core would break at almost the same time, but to achieve this, the steel core must be pretensioned to give permanent strain and the elongation at break of the steel core and aluminum wire should be brought closer together.
It is effective to increase the shared load of the steel core.

The present invention was made in view of the above circumstances, and its purpose is to provide a method for manufacturing ACSR wire with increased stranded wire strength. This is achieved by arranging a braking device and a pulling device between the braking device and the pulling device, and applying permanent strain to the steel core between the braking device and the pulling device.

An embodiment of the present invention will be described below with reference to the drawings.

Fig. 2 shows the conventional ACSR wire manufacturing method, in which a steel core strand 5 is drawn out from a drum 4 loaded in a steel core supply device 3, passed through a guide roller 6, and then transferred to an aluminum stranding machine 7. Aluminum wires are twisted on the steel core 5 in the first cage 8 and the second cage 9, respectively. In this case, the twisting operation is performed while applying an appropriate brake to the drum 4 and adjusting the tension of the steel core, and no tension is applied that would cause permanent distortion to the steel core.

FIG. 3 shows the method of the present invention, in which the same parts as in FIG. 2 are designated by the same reference numerals. In this figure, an endless track type braking device 10 and a take-off device 11 are arranged between a steel core supply device 3 and an aluminum twisting machine 7, and by adjusting their speeds, the braking device 10 and take-off device 11 are arranged between a steel core supply device 3 and an aluminum twisting machine 7. Steel core 5' between device 11
A pretension is added to the It is desirable that the permanent strain given to the steel core 5' by pretension is applied so that the difference between the elongation at break of the steel core and the elongation at break is approximately equal to the elongation at break of the aluminum wire. The wires break almost simultaneously, and the shared load of the steel core can be maximized.

As described above, according to the present invention, permanent strain can be imparted to the steel core constituting the ACSR wire, increasing the shared load of the steel core and increasing the stranded wire strength.
ACSR wire can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an ACSR wire, FIG. 2 is a conventional method for manufacturing a stranded wire, and FIG. 3 is a method for manufacturing a stranded wire according to the present invention. 1... Galvanized steel wire, 2... Aluminum wire, 5
... Steel core, 7 ... Aluminum twisting machine, 10 ... Braking device, 11 ... Taking device.

Claims (1)

[Claims] 1. In a method for manufacturing a steel-core aluminum stranded wire in which multiple aluminum or aluminum alloy strands are twisted around the outer circumference of a steel core, a braking device and a take-off device are arranged between a steel core supply device and an aluminum stranding machine. However, between the braking device and the pulling device, the steel core is subjected to a permanent process in advance so that the difference between the elongation at break of the steel core and the strain applied to the steel core is approximately equal to the elongation at break of the aluminum or aluminum alloy strand. A method for manufacturing stranded wire characterized by subjecting it to distortion.