In practical applications, due to the relatively high volume requirements of the winding wire, the substitution effect of aluminum on copper is not particularly obvious; however, in the field of power lines and communication lines, the situation is much more serious. In the field of radio frequency signal transmission, CCA (Cooper Clad Aluminum) materials are quite capable of replacing copper. The copper clad aluminum is a concentrically coated copper layer on the surface of an aluminum or aluminum steel alloy core material. According to different specifications, the weight ratio of copper is mainly between 15% and 25%. Due to the skin effect of high-frequency signal transmission, the cable TV signal is transmitted over the surface of the copper layer over 0.008 mm, and the copper-clad aluminum inner conductor can fully meet the signal transmission requirements, and its signal transmission characteristics are consistent with the copper wire of the same diameter.
The “copper-aluminum dispute” in the cable industry lasted for many years, especially when copper prices remained high and the profit rate of cable manufacturers declined sharply. The call for “aluminum section copper” or even “aluminum substitute copper” was particularly high. . However, there are different opinions on whether or not "aluminum section copper" is feasible. Some use Europe and the United States as an example to prove the reliability of aluminum alloy cables. On the other hand, they use other proof materials to show that there are certain differences between aluminum alloy and copper core cables. Therefore, the "copper-aluminum dispute" has been difficult to distinguish between high and low, and the development of aluminum alloy cables has also been stagnant.
In 2006, the State Bureau of Quality and Technical Supervision and the Ministry of Construction issued the "Code for the Design of Housing Construction", which gave cold water to the aluminum alloy cables. In the "House Design Standards" section on electrical matters, the "wires should be clearly established." Copper wire regulations." Since then, copper-core cables have continued to prevail, and “copper-aluminum” has turned into an industry appeal, but no relevant policies have escorted them.
However, this situation has finally changed recently. Recently, at the Wire and Cable Summit jointly organized by the National Quality Inspection Center and the Anhui Provincial Government, the Ministry of Industry and Information Technology was known as an aluminum alloy cable. The Ministry of Industry and Information Technology said that it will guide enterprises to actively develop key technologies, cutting-edge technologies, and basic technologies, through technologies. Innovation accelerates industrial restructuring. Promote the natural cross-linking cable process, promote the application of circulating water cooling or air-cooled technology, accelerate the research and development of high-efficiency cable material equipment, research and development of silane-cross-linked ethylene-propylene rubber cables, and the research and utilization of silane-crosslinked polyethylene cable insulation.
At the recent "Aluminum Section Copper Symposium," the Ministry of Industry and Information Technology and the National Development and Reform Commission have stated that they will expand the use of aluminum in the power industry and thus replace copper. It is reported that cables using aluminum alloy as the core wire can be used in large quantities in low-voltage buildings, structures, and ancillary facilities. As a result, the problem of high copper prices and high product prices and low profit margins in the domestic cable industry can be alleviated. According to the data provided by the Ministry of Industry and Information Technology, in 2012, the amount of copper used in the domestic wire and cable industry increased gradually, of which the power grid industry used more than 5 million tons of copper, accounting for more than 60% of domestic copper consumption. It can be seen that aluminum alloy cable technology and aluminum-clad copper technology will usher in great development in the future, which may also contribute to the development of the entire cable industry.
The reason why there is so much diغير مجاز مي باشدreement between copper conductors and aluminum conductors is that there is a large part of the reason that the copper sellers and aluminum sellers are not all considering the development of the cable industry. Copper development, manufacturing, and sales parties naturally expect the cable industry to use more copper materials. Conversely, aluminum development, manufacturing, and sales parties hope that the cable industry will use aluminum. But for the cable industry, that kind of material has stable performance, low غير مجاز مي باشدt, and natural is the fundamental condition for being selected.
From the غير مجاز مي باشدt point of view, the price of aluminum is naturally much lower than that of copper, so the key to the problem lies in the performance of the two. Since the specific gravity of copper is 8.96 g/cm3, which is 3.65 times that of aluminum (2.7 g/cm3), the resistivity of copper is 0.01851 Ωmm2/m, which is 63% of aluminum (0.0294 Ω"mm2/m). According to the national recommendation, at a temperature of 20°C, the DC resistance of a section of copper is equivalent to that of two large aluminum counterparts. In theory, the use of aluminum as the raw material of wire and cable is more غير مجاز مي باشدt-effective than copper.
1. DC resistivity: The resistivity of copper clad aluminum wire is larger than that of pure copper wire, which is about 1.5 times that of pure copper wire. When the resistance is the same (larger cross-sectional area than copper), the weight of copper clad aluminum wire is about pure copper. 1/2 of the line. According to the skin effect calculation, the resistivity is equal to that of a copper conductor of the same cross section at high frequencies above 50 MHz. In the use of 50Hz frequency power cables, the skin effect and proximity effect of the copper conductors gradually become more than 150mm2. At the same time, due to the start-up and operation of the equipment power of industrial and mining enterprises (such as high-frequency furnaces, high-power motors, etc.) In case of failure, energy sources that generate higher-order harmonic currents are injected into the power supply system, generating higher-order harmonic voltages at the corresponding frequencies in the impedance of the system, causing the voltage waveform to be distorted, increasing the losses in the power supply system, and increasing the conductor heating.
With the continuous optimization of aluminum alloy cable and aluminum-based copper technology in recent years, its performance has also greatly improved. Here, taking the relatively mature and popular copper-clad aluminum power cables and wires and cables used in electrical equipment as examples, we see that the advantages are very obvious.
In addition, the cables magnify the harmonics, causing excessive voltage at the connectors and damaging the cable heads. The use of copper-clad aluminum conductors acts to reduce the AC impedance (resistance) produced by higher harmonics. In other occasions, by increasing the volume of copper in the copper clad aluminum monofilament and corresponding technological measures, the copper clad aluminum conductor meets the DC resistance requirements of the conductor within the upper limit of the current outer diameter of the same specification conductor.
2. The use of copper-clad aluminum conductors can meet the current practice of product selection, design, use, and installation for wire and cable that has lasted for many years, and it is also advantageous for tight pressing and tin soldering of cable terminals.
3. Reduce the AC resistance: AC resistance is the main basis of the current carrying capacity. According to the principle of skin effect, the surface of a single wire has a larger current per unit area than the current per unit area of the wire. In other words, the center of a large-section conductor is in the area of a circle composed of the same conductor, and the center of the circle is smaller than the current passed through the circumference. Therefore, it is most reasonable and economical to use a different metal for the center conductor and the circumference conductor.
In addition, the impact of AC resistance indicators in addition to DC resistance, skin effect, there is a proximity effect, compared with the same DC resistance of the copper conductor, the cross-section should be used to enlarge the copper-clad aluminum conductor, in a single conductor, aluminum in the center, Copper is in the outer circle; the enlarged copper-clad aluminum conductor increases the total cross-section of the conductor, so it also increases the surface area of the conductor, improves the heat dissipation conditions of the cable, and increases the heat dissipation area. The thermal conductivity of aluminum is similar to that of copper and is equivalent. Under the condition of material غير مجاز مي باشدt, AC resistance indicators are much more economical.
4. Low غير مجاز مي باشدt and light weight: Copper-clad aluminum conductor cables can save more than 40% of the غير مجاز مي باشدt compared with copper core wires of the same specifications. The proportion of copper clad aluminum wire is only 37%-40% of that of pure copper wire. When the wire diameter and weight are equal, its length is 2.5 times that of pure copper wire.
5. Has good corrosion resistance: Aluminum is more easily corrosive than copper, but due to the complete metallurgy of the copper clad aluminum material, the aluminum is completely covered with copper and will not be contacted by water and air, and it fully achieves the same performance as copper. For aluminum conductors, especially in coastal areas, the chloride ions contained in the salt fog in the atmosphere will condense on the surface of aluminum, causing localized corrosion around the surface impurities and defects, forming holes, cracks, and micro-cells, exacerbating the corrosion of aluminum conductors. .
6. Good weldability: The copper clad aluminum wire is coated with a layer of pure copper concentrically, so it has the same solderability as the pure copper wire, which is convenient for production.
In addition, with the advancement of the "copper-based copper" business, domestic cable products will have lower prices and more stable performance, which will be conducive to international competition. Therefore, the use of low-priced magic weapons (inexpensive goods at a low price) will be used positively rather than at the expense of quality. . It can be seen that through continuous maturation of technology and continuous research and development of new technologies, “copper-aluminum” will be more effective, and aluminum alloy cables may lead the domestic cable industry toward greater development.
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The power tool industry has actively introduced technology to promote its own strength, China's rapid development, and the integration of foreign exchanges. In the power tool industry, rapid development has occurred in recent years, but in comparison with foreign related companies or at a backward level. Luo Baihui believes that this technology is very important for the rapid development of the electric tool industry. The power tool industry is a high-tech industry. Enterprises must actively introduce relevant technologies and enhance their own strength. 
