Applications in the electrical industry
Power transmission: A large amount of highly conductive copper is consumed in power transmission, mainly used in power cables, buses, transformers, switches, plug-in components and connectors. In the process of power transmission of wires and cables, electric energy is wasted due to resistance heating. From the perspective of energy saving and economy, the "optimal cable cross-section" standard is currently being promoted in the world. In the past, the popular standards were simply based on reducing the investment in the first installation, and in order to minimize the cable cross-section, the minimum allowable size of the cable was determined to prevent dangerous overheating under the rated current required by the design. Although the installation fee of the cable laid according to this standard is low, the resistance energy consumption is relatively large during long-term use. The "optimal cable cross-section" standard takes into account both the first installation cost and the power consumption, and appropriately enlarges the cable size to achieve energy saving and the best comprehensive economic benefits. According to the new standard, the cable cross-section is often more than doubled than the old standard, which can achieve an energy saving effect of about 50%. In the past period of time, due to the shortage of steel in my country, aluminum was used to replace copper in overhead high-voltage transmission lines in the hope of reducing weight, considering that the specific gravity of aluminum is only 30% of that of copper. At present, from the perspective of environmental protection, aerial transmission lines will be converted to laying underground cables. In this case, aluminum pales in comparison with copper due to its poor conductivity and large cable size.
Motor manufacturing: In motor manufacturing, high-conductivity and high-strength copper alloys are widely used. The main copper parts are stators, rotors, and shaft heads. In large motors, the windings are cooled with water or hydrogen, which is called double water internal cooling or hydrogen cooling motors, which requires a long length of hollow wire. Motors are large users of electricity, accounting for about 60% of the total electricity supply. The cumulative electricity bill for the operation of a motor is very high, generally reaching the cost of the motor itself within the first 500 hours of operation, equivalent to 4 to 16 times the cost within a year, and up to 200 times the cost during the entire working life. A small increase in motor efficiency can not only save energy; but also obtain significant economic benefits. The development and application of high-efficiency motors is a hot topic in the world today. Since the energy consumption inside the motor mainly comes from the resistance loss of the winding, increasing the cross-section of the copper wire is a key measure to develop high-efficiency motors. In recent years, some high-efficiency motors that have been developed first have increased the use of copper windings by 25% to 100% compared with traditional motors. At present, the U.S. Department of Energy is funding a development project to produce motor rotors using cast copper technology.
Communication cables: Since the 1980s, due to the advantages of large current carrying capacity of optical fiber cables, they have been replacing copper cables on communication trunk lines and have been rapidly promoted and applied. However, a large amount of copper is still needed to convert electrical energy into light energy and input lines to users. With the development of the communication industry, people are increasingly dependent on communication, and the demand for optical fiber cables and copper wires will continue to increase.
Residential electrical lines: In recent years, with the improvement of people's living standards in my country, household appliances have been rapidly popularized, and residential electricity load has grown rapidly. In 1987, residential electricity consumption was 26.96 billion kWh (1 kWh = 1 kilowatt-hour), and ten years later in 1996 it soared to 113.1 billion kWh, an increase of 3.2 times. Despite this, there is still a big gap compared with developed countries. For example, in 1995, the per capita electricity consumption in the United States was 14.6 times that of my country, and Japan was 8.6 times that of my country. my country's residential electricity consumption will still have great development in the future. It is expected to increase by 1.4 times from 1996 to 2005.
Application in machinery and metallurgical industry: Copper parts can be found in almost all machines. In addition to the large amount of steel used in motors, circuits, hydraulic systems, pneumatic systems and control systems, there are many kinds of transmission parts and fixing parts made of brass and bronze, such as gears, worm wheels, worms, couplings, fasteners, twisting parts, screws, nuts, etc., which are everywhere. Bearings or sleeves made of anti-friction copper alloys are used between almost all parts that make mechanical relative motion, especially the cylinder sleeves and slides of large extruders and forging presses of 10,000 tons are almost all made of bronze, and the weight of castings can reach several tons. Many elastic elements almost all use silicon bronze and tin bronze as materials. Welding tools, die-casting molds, etc. are even more inseparable from copper alloys, and so on.
Metallurgical equipment: The metallurgical industry is a major consumer of electricity and is known as the "electric tiger". In the construction of a metallurgical plant, it is usually necessary to have a huge transmission and distribution system and power operation equipment that rely on copper to work. In addition, in pyrometallurgy, continuous casting technology has dominated, and the key component, the crystallizer, is mostly made of high-strength and high-thermal-conductivity copper alloys such as chromium copper and silver copper. The water-cooled crucibles of vacuum arc furnaces and electric slag furnaces in electrometallurgy are made of steel pipes, and the induction coils of various induction heating are wound with copper pipes or special-shaped copper pipes, and water is passed through the inside for cooling.
Alloy additives: Copper is an important additive element in alloys such as steel and aluminum. A small amount of copper (0.2-0.5%) added to low-alloy structural steel can improve the strength of the steel and its resistance to atmospheric and marine corrosion. Adding copper to corrosion-resistant cast iron and stainless steel can further improve their corrosion resistance. High-nickel alloys containing about 30% copper are the famous high-strength and corrosion-resistant "monel alloys", which are widely used in the nuclear industry. Copper is contained in many high-strength aluminum alloys. Through quenching and aging heat treatment, dispersed fine particles are precipitated in the alloy, which significantly improves its strength, and is called age-hardened aluminum alloy. Among them, the most famous is duralumin or hard aluminum, which is an aluminum alloy containing copper, manganese and magnesium, and is an important structural material for manufacturing aircraft and rockets.
