CN101948988A - Method for manufacturing CNT (carbon nanotube) composite transmission conductor - Google Patents

Abstract

A method for manufacturing a carbon nanotube composite transmission wire. The multi-walled carbon nanotube powder accounting for 1% to 7% of the total mass is filled in small holes drilled evenly on an electrical aluminum block, and two blocks of multi-walled carbon have been added. The aluminum blocks of nanotube powder are stacked together in the opposite direction of the blind hole method. After the friction extrusion process is made into a composite material, it is continuously rolled and drawn into the required round wire of carbon nanotube/aluminum matrix composite material. Finally, stranding is carried out on a stranding machine, and a single-strand carbon nanotube composite power transmission wire is obtained through a twist-back and stress-relief device. The invention has the advantages of: 1) the wire has a small coefficient of linear expansion, strong thermal deformation resistance, can reduce the influence of temperature on sag changes, improve sag characteristics, improve the safety of overhead lines and reduce line construction costs; 2) has It is beneficial to improve the conductivity of the wire along the line and further reduce the transmission loss; 3) The process is relatively simple, and there will be no loosening or slipping of the composite core and the aluminum stranded wire due to various reasons.

Description

A kind of manufacturing method of carbon nanotube composite transmission wire

technical field

The invention relates to a method for manufacturing a composite power transmission wire, in particular to a method for manufacturing a carbon nanotube composite power transmission wire.

Background technique

The transmission wires of traditional overhead lines are mostly steel-cored aluminum stranded wires, and there are many problems in actual use: such as: 1) The reinforced steel core greatly increases the weight of the wires, so the span between the towers of overhead lines needs to be short or Strengthen the strength of the tower, otherwise the load capacity of the tower is not enough, so the cost of the line will increase; 2) The existing magnetic loss and thermal effect will make the transmission loss of the line large; 3) The linear expansion coefficient of the steel core is large, and the change of working conditions will make the arc of the wire 4) The electrochemical corrosion between the aluminum wire and the galvanized steel core reduces the service life of the wire.

With the rapid development of my country's economy, the construction of the electric power industry is advancing by leaps and bounds, and higher requirements are put forward for overhead transmission wires. In order to overcome the defects of steel-reinforced aluminum stranded wire, carbon fiber composite core wires have appeared, such as Chinese patents CN1649718, CN201237921, etc. This type of wire has high specific strength, high temperature resistance, fatigue resistance, low laxity, and small linear expansion coefficient. Features, the advantages in the transmission wire are becoming more and more prominent.

A key factor determining the performance of fiber reinforced composites is the aspect ratio. As a one-dimensional nanomaterial, carbon nanotubes have a huge aspect ratio (generally above 1000:1) and are expected to be used as tough carbon fibers, which are far superior to any fiber in terms of strength and toughness, so they are considered to be the future " "Super fiber", the application of carbon nanotubes in power transmission wires, from a theoretical point of view, the performance far exceeds that of carbon fiber composite core wires. However, related to the inherent physical and chemical properties of nanophases, the preparation of nanophase-reinforced composites is much more complicated and difficult than that of ordinary composites. For example, at present, the preparation of carbon nanotubes/aluminum matrix composites at home and abroad mainly adopts powder metallurgy method, melt impregnation method, in-situ synthesis method, high energy ball milling method, rapid solidification method, electroless plating method, plasma spray molding method, etc. Both methods need to pre-prepare the powder mixture of carbon nanotubes and aluminum matrix, the dispersion of carbon nanotubes in the matrix is restricted, and methods such as high-energy ball milling will also cause damage to the perfect structure of carbon nanotubes, thereby weakening the excellent performance of composite materials .

Contents of the invention

The purpose of the present invention is to provide a method for manufacturing a carbon nanotube composite power transmission wire. The prepared single-strand power transmission wire aluminum matrix has fine grains, carbon nanotubes are uniformly dispersed and basically oriented along the line, which is conducive to exerting the advantages of carbon nanotube composite materials. Advantages, improve the strength and toughness of aluminum wires and increase the conductivity along the line direction, reduce transmission loss, etc.

The present invention is realized in this way, which is characterized in that the powder of multi-walled carbon nanotubes accounting for 1% to 7% of the total mass is filled in the uniformly drilled small holes on the electrical aluminum block, and two pieces of multi-walled carbon nanotubes have been added The aluminum blocks of the tube powder are stacked together in the opposite direction of the blind hole, so that the multi-walled carbon nanotube powder can be wrapped in it, and then through the friction extrusion process, a high-speed rotating friction head in the middle and a ring around the friction head are formed. The metal flow channel with small gaps, the high-speed rotating friction head is inserted into the aluminum block added with multi-walled carbon nanotube powder, and under the extrusion of the extrusion rod, the aluminum block added with multi-walled carbon nanotube powder is extruded to the friction The head is broken and passed through the metal flow channel, the rotation speed of the friction head is 480-720r/min, the extrusion speed of the extrusion rod is 24-36mm/min, and the obtained carbon nanotube/aluminum matrix composite material is continuously rolled into a continuous rolling mill Rod, the composite material is rolled at a temperature of 500°C to 600°C, and rolled out at a temperature of 150°C to 350°C. After continuous rolling, the wire is drawn on a continuous, high-speed aluminum alloy wire drawing machine at a speed of 20-30m/s. After 13 passes The second drawing wire is drawn into the required round wire of carbon nanotube/aluminum matrix composite material, and finally, it is twisted on the stranding machine, and the single-strand carbon nanotube composite transmission wire is obtained through the back-twisting stress relief device.

The advantages of the present invention are: 1) Friction extrusion is beneficial to the compounding of carbon nanotubes and matrix metal, so that they can be evenly dispersed in the matrix, which can greatly improve the mechanical and thermal properties of the material. The grains are refined, which is also conducive to the improvement of its strength and toughness. Therefore, it is not necessary to use steel core or composite core reinforcement to increase the strength of the wire, which can greatly reduce the weight of the wire. At the same time, it can overcome the thermal effect caused by the magnetic loss of the steel core wire. The bimetallic corrosion between the aluminum wire and the galvanized steel core reduces the transmission loss and improves the corrosion resistance of the wire; the wire has a small linear expansion coefficient and strong resistance to thermal deformation, which can reduce the influence of temperature on sag changes and improve the sag characteristics , improve the safety of overhead lines and reduce the cost of line construction; 2) After continuous rolling and multi-pass wire drawing, it is helpful for carbon nanotubes to be oriented in the axial direction, based on the super conductivity of carbon nanotubes and the conductivity of composite materials The anisotropy is conducive to improving the conductivity of the wire along the line and further reducing the transmission loss; 3) Unlike most carbon fiber composite core transmission wires that use carbon fiber resin-based composite cores, carbon nanotubes are directly composited with aluminum matrix, and the process is relatively simple , There will be no loosening or slipping of the composite core and aluminum stranded wire due to various reasons.

Detailed ways

Example 1

The present invention is achieved in this way, the multi-walled carbon nanotube powder that accounts for 1% of the total mass is filled in the well-drilled holes on the electrical aluminum block, and the two aluminum blocks that have been added with the multi-walled carbon nanotube powder are The blind hole method is stacked together in the opposite way, so that the multi-walled carbon nanotube powder can be wrapped in it, and then the high-speed rotating friction head is inserted into the aluminum block to which the multi-walled carbon nanotube powder has been added. The rotation speed of the friction head is 480r/min, extrusion rod extrusion speed 24mm/min, the obtained carbon nanotube/aluminum matrix composite material is continuously rolled into a rod in the continuous rolling unit, the composite material is rolled at a temperature of 500°C, and the rolling temperature is 150°C. After rolling, the wire is drawn on a continuous, high-speed aluminum alloy wire drawing machine with a drawing speed of 20m/s. After 13 passes of drawing, the required carbon nanotube/aluminum matrix composite material round wire is drawn, and finally, it is drawn on the stranding machine Straining is carried out, and a single-strand carbon nanotube composite power transmission wire is obtained through a device for untwisting and stress relief. The results show that the average tensile strength of the prepared carbon nanotube composite transmission wire can reach 255MPa, and the average electrical conductivity is 50.3% IACS (single wire diameter 4.63mm). The average rate is 49.8% IACS) has improved to a certain extent.

Example 2

The present invention is achieved in this way, the multi-walled carbon nanotube powder that accounts for 5% of the total mass is filled in the well-drilled small hole on the electrical aluminum block, and two aluminum blocks that have added the multi-walled carbon nanotube powder are The blind hole method is stacked together in the opposite way, so that the multi-walled carbon nanotube powder can be wrapped in it, and then the high-speed rotating friction head is inserted into the aluminum block to which the multi-walled carbon nanotube powder has been added. The rotation speed of the friction head is 600r/min, extrusion rod extrusion speed 30mm/min, the obtained carbon nanotube/aluminum matrix composite material is continuously rolled into a rod in the continuous rolling unit, the composite material is rolled at a temperature of 550°C, and the rolling temperature is 200°C. After rolling, the wire is drawn on a continuous, high-speed aluminum alloy wire drawing machine at a speed of 25m/s. After 13 passes of drawing, the required carbon nanotube/aluminum matrix composite material round wire is drawn, and finally, on the stranding machine Straining is carried out, and a single-strand carbon nanotube composite power transmission wire is obtained through a device for untwisting and stress relief. The results show that the average tensile strength of the prepared carbon nanotube composite transmission wire can reach 321MPa, and the average conductivity is 51.2%IACS, while the measured average tensile strength of ordinary electrical aluminum wire is 215MPa, and the average conductivity is 49.8%IACS (single wire diameter 4.63mm).

Example 3

The present invention is achieved in this way, the multi-walled carbon nanotube powder that accounts for 7% of the total mass is filled in the well-drilled holes on the electrical aluminum block, and the two aluminum blocks that have added the multi-walled carbon nanotube powder are The blind hole method is stacked together in the opposite way, so that the multi-walled carbon nanotube powder can be wrapped in it, and then the high-speed rotating friction head is inserted into the aluminum block to which the multi-walled carbon nanotube powder has been added. The rotation speed of the friction head is 720r/min, extrusion rod extrusion speed 36mm/min, the obtained carbon nanotube/aluminum matrix composite material is continuously rolled into a rod in the continuous rolling unit, the composite material is rolled at a temperature of 600°C, and the rolling temperature is 350°C. After rolling, the wire is drawn on a continuous, high-speed aluminum alloy wire drawing machine at a speed of 30m/s. After 13 passes of wire drawing, the required carbon nanotube/aluminum matrix composite material round wire is drawn, and finally, on the stranding machine Straining is carried out, and a single-strand carbon nanotube composite power transmission wire is obtained through a device for untwisting and stress relief. The results show that the average tensile strength of the prepared carbon nanotube composite transmission wire can reach 346MPa, and the average conductivity is 51.5%IACS, while the measured average tensile strength of ordinary electrical aluminum wire is 215MPa, and the average conductivity is 49.8%IACS (single wire diameter 4.63mm).

Claims (1)

1. A method for manufacturing a carbon nanotube composite transmission wire, which is characterized in that the multi-walled carbon nanotube powder accounting for 1% to 7% of the total mass is filled in the well-drilled small hole on the electrical aluminum block, and the two blocks are The aluminum blocks with added multi-walled carbon nanotube powder are stacked together in the opposite direction of the blind hole, so that the multi-walled carbon nanotube powder can be wrapped in it, and then through the friction extrusion process, a high-speed rotating friction in the middle is formed. There are metal flow channels with small gaps around the head and the friction head. Insert the high-speed rotating friction head into the aluminum block that has added multi-wall carbon nanotube powder. Under the extrusion of the extrusion rod, the multi-wall carbon nanotube powder has been added. The aluminum block extrudes to the friction head and is crushed through the metal flow channel. The rotation speed of the friction head is 480-720r/min, and the extrusion speed of the extrusion rod is 24-36mm/min. The carbon nanotube/aluminum matrix composite material obtained is The continuous rolling unit is continuously rolled into rods, the composite material is rolled at a temperature of 500°C-600°C, and the rolling temperature is 150°C-350°C. After continuous rolling, the wire is drawn on a continuous, high-speed aluminum alloy wire drawing machine, and the wire drawing speed is 20-30m /s, after 13 times of wire drawing, the required carbon nanotube/aluminum matrix composite round wire is drawn, and finally, it is twisted on the stranding machine, and the single-strand carbon nanotube is obtained through the back-twisting stress relief device Composite transmission conductors.