There are three ways to categorize copper alloys: power transmission
Power transmission requires a large consumption of highly conductive copper, which is mainly used for power wires and cables, busbars, transformers, switches, plug-in components and couplings.
In the power transmission process of wire and cable, due to resistance to heat and waste of electricity. From the point of view of energy saving and economy, the world is now promoting the optimal cable cross-section standards. Popular standards in the past, purely from the point of view of reducing the investment in a single installation, in order to minimize the cable cross-section, in order to the design requirements of the rated current, without dangerous overheating, to determine the minimum allowable size of the cable. The cable laid according to this standard, although the installation cost is low; but in the long-term use of the process, resistance energy consumption is relatively large. The optimal cable cross-section standards, taking into account the two factors of primary installation costs and power consumption, appropriate enlargement of the cable size, in order to achieve energy saving and the best overall economic efficiency. In accordance with the new standards, cable cross-section is often more than double the old standard, you can get about 50% of the energy-saving effect.
China in the past period of time, due to the steel supply exceeds demand, taking into account the specific gravity of aluminum is only 30% of copper, in the hope of reducing the weight of the overhead high-voltage transmission lines had taken aluminum instead of copper measures. underground cables. In this case, aluminum is dwarfed by the disadvantages of poor electrical conductivity and large cable size compared to copper.
For the same reason, it is wise to replace old aluminum-wound transformers with energy-efficient copper-wound transformers.
Motor manufacturing
In motor manufacturing, the extensive use of high conductivity and high strength copper alloy. The main copper parts are stator, rotor and shaft head. In large motors, the windings are cooled with water or hydrogen, called double water-cooled or hydrogen-cooled motors, which requires large lengths of hollow conductors.
Motors are large users of electrical energy, accounting for about 60 percent of all electrical energy supplied. A motor running the cumulative electricity costs are high, generally in the initial operation of 5 00 hours to reach the cost of the motor Benyi, the equivalent of 4 to 16 times the cost in a year, in the entire working life of the cost can be up to 200 times. A small increase in the efficiency of the motor, not only can energy saving; and can obtain significant economic benefits. The development and application of high-efficiency motors is currently a hot topic in the world. Since the energy consumption inside the motor mainly comes from the resistance loss of the windings; therefore, increasing the copper wire cross-section is a key measure for the development of high-efficiency motors. And the first to develop a number of high-efficiency motors compared with conventional motors, the use of copper windings increased by 25 to 100%. The U.S. Department of Energy is funding a development program to use cast-in copper technology to produce motor rotors.
Communication cables
Since the 80's, due to the fiber optic cable current-carrying capacity and other advantages, in the communication trunk lines continue to replace the copper cable, and the rapid popularization of the application. However, the conversion of electrical energy into light energy, as well as the input user lines still need to use a lot of copper. With the development of the communications business, people rely more and more on communications, the demand for both fiber optic cables and copper wires will continue to increase.
Residential electrical wiring
With the improvement of the standard of living of the people of China, the rapid popularization of home appliances, residential electricity load is growing rapidly. As shown in Figure 6.6, residential electricity consumption in 1987 was 26.96 billion degrees (l degrees = 1 kW?). hour) in 1987, 10 years later in 1996 jumped to 113.1 billion degrees, an increase of 3.2 times. Nevertheless, there is still a big gap compared with developed countries. For example, in 1995, the per capita electricity consumption of the United States was 14.6 times that of our country, and that of Japan was 8.6 times that of our country. China's residential electricity consumption will continue to develop greatly in the future. It is expected that from 1996 to 2005, but also to grow l.4 times. The electronics industry is a new industry, in the process of its flourishing development, the continuous development of new steel products and new areas of application. Its application from the electric vacuum devices and printed circuits, the development of microelectronics and semiconductor integrated circuits.
Electro-vacuum devices
Electro-vacuum devices are mainly high-frequency and ultra-high-frequency transmitter tubes, waveguides, magnetrons, etc., which require high-purity oxygen-free copper and diffusion-enhanced oxygen-free copper.
Printed circuits
Copper printed circuits, copper foil as a surface, pasted on a plastic plate as a support; photographic method of circuit wiring diagram printed on the copper plate; through the etching of the excess part of the removal and leave the interconnection of the circuit. Then, in the printed circuit board and the external connections punched holes, the discrete components of the connector or other parts of the terminal inserted, soldered to the mouth of the road, so that a complete line will be assembled. If the dip-plating method is used, the soldering of all the connectors can be done at once. In this way, for those occasions that require fine arrangement of circuits, such as radio, television, computers, etc., the use of printed circuits can save a lot of wiring and fixing the circuit of the labor; and therefore widely used, need to consume a lot of copper foil. In addition, in the connection of the circuit also need to use a variety of inexpensive, low melting point, good fluidity of copper-based brazing materials.
Integrated circuits
The core of microelectronics technology is integrated circuits. Integrated circuits refers to the semiconductor crystal material as a substrate (chip), the use of specialized process technology will constitute the circuit components and interconnections integrated in the substrate within, on the surface or on top of the substrate micro-miniaturized circuits. Such microcircuits are structurally thousands of times smaller in size and weight than the most compact discrete component circuits. Its emergence caused a huge change in computers and became the basis of modern information technology. The development of ultra-large-scale integrated circuits, smaller than a small fingernail on a single chip area, can make the number of transistors, has reached 100,000 or even more than a million. Internationally renowned computer company IBM (International Business Machines Corporation), has used copper instead of aluminum in the silicon chip for the interconnect line, a breakthrough. This new type of microchip with copper, you can get 30% of the performance gain, the circuit line size can be reduced to 0.12 microns, so that the number of transistors integrated in a single chip up to 2 million. This for the ancient metal copper, in the semiconductor integrated circuits in this latest technology field of application, opened up a new situation.
Leadframes
In order to protect the proper functioning of an integrated circuit or hybrid circuit, it needs to be encapsulated; and when encapsulated, a large number of connectors in the circuit are led out of the hermetically sealed body. These leads require a certain degree of strength, constituting the integrated package circuit support skeleton, known as the lead frame. In practice, in order to high-speed mass production, the lead frame is usually in a metal belt according to a specific arrangement of continuous stamping and become. The frame material accounts for 1/3 ~ l/4 of the total cost of the integrated circuit, and the dosage is very large; therefore, it is necessary to have a low cost.
Copper alloy is inexpensive, has high strength, electrical and thermal conductivity, processing performance, pin welding and corrosion resistance is excellent, through the alloying can be in a wide range of control of its performance, can better meet the performance requirements of the lead frame, has become an important material for the lead frame. It is currently the largest amount of copper in microelectronic devices in a material. Ship
Because of the good corrosion resistance of seawater, many copper alloys, such as: aluminum bronze, manganese bronze, aluminum brass, gunmetal (tin-zinc bronze), white steel, and nickel-copper alloy (Monel alloy) has become the standard material for shipbuilding. Generally in the warships and merchant ships in the weight, copper and copper alloys accounted for 2 ~ 3%.
Warships and most of the large merchant ships propellers are made of aluminum bronze or brass. Screwdrivers for large ships weigh 20 to 25 tons each. Queen Elizabeth and Queen Mary aircraft carrier propeller weighs 3 5 tons each. Admiralty gunmetal is commonly used for the heavy stern shafts of large ships, and the same material is used for the conical bolts of the rudders and propellers. Steel and copper alloys were also used extensively in the engines and boiler rooms. The world's first nuclear-powered merchant ship used 30 tons of white copper condenser tubes. Aluminum-brass tubes were used as large heating coils for oil tanks, and there were 12 such tanks on a 100,000-ton ship, with a corresponding heating system of considerable size. The ship's electrical equipment is also very complex, engines, electric motors, communication systems, etc. almost entirely rely on copper and copper alloys to work. The cabins of ships of all sizes were often decorated with steel and copper alloys. Even small wooden boats are best secured to wooden structures with screws and nails made of steel alloys (usually silicon bronze), which can be mass-produced by rolling.
To prevent the hull from being fouled by sea creatures that would interfere with navigation, it is often protected by cladding it with copper; or by painting it with copper-containing paint.
In World War II, in order to prevent German magnetic mine attacks on ships, had developed anti-magnetic mine device, in the steel hull around the attached a circle of copper tape, pass the electric current in order to neutralize the ship's magnetic field, so that you can not detonate the mine. From 1944 onwards, all Allied ships, ***about 18,000 in number, were fitted with such demagnetizing devices and protected. Some of the larger main ships required large amounts of copper for this purpose, for example, one of them had 28 miles of de-magnetized copper wire and weighed about 30 tons.
Automobiles
Copper for automobiles is 10 to 2I kilograms per vehicle, varying with the type and size of the vehicle, and accounting for about 6 to 9% of the weight of a small car. Copper and copper alloys are mainly used in radiators, brake system piping, hydraulics, gears, bearings, brake friction pads, power distribution and electrical systems, gaskets, and a variety of joints, fittings and trim, and so on. One of the larger uses of steel is in radiators. Modern tube-and-belt radiators use brass bands soldered into radiator tubes and thin copper bands bent into fins.
In order to further improve the performance of copper radiators, enhance its competitiveness against aluminum radiators, made many improvements. In terms of material, to add trace elements to copper, in order to achieve the premise of no loss of thermal conductivity, to improve its strength and softening point, thereby reducing the thickness of the strip, saving the amount of steel; in the manufacturing process, the use of high-frequency or laser welding of copper tubes, and the use of steel brazing instead of lead contamination susceptible to soft soldering to assemble the core of the heat sink. The results of these efforts are shown in Table 6.2, compared with brazed aluminum radiators, in the same heat dissipation conditions, that is, in the same air and coolant pressure drop, the new copper radiators are lighter in weight and significantly reduced in size; coupled with steel's corrosion resistance and long service life, the advantages of copper radiators are even more obvious. In addition, in order to protect the environment, vigorously promote and develop electric vehicles, the amount of steel used per car will increase exponentially.
Railway
The electrification of the railroad has a great need for copper and copper alloy. Over 2 tons of shaped copper wire is required for each kilometer of overhead conductor. In order to improve its strength, often add a small amount of copper (about 1%) or silver (about of%). In addition, trains rely on copper and copper alloys for motors, rectifiers, and control, braking, electrical and signaling systems.
Aircraft
Aircraft navigation is also inseparable from copper. For example: aircraft wiring, hydraulic, cooling and pneumatic systems need to use copper, bearing retainers and landing gear bearings using aluminum bronze tubing, navigation instrumentation application of anti-magnetic steel alloys, the use of many of the instrumentation broken copper elastic components and so on. Light industrial products are closely related to people's lives, with a wide variety of varieties. Due to the copper has a good overall performance, everywhere you can see it to show its hand. Now only a few examples are as follows:
Air conditioners and freezers
Air conditioners and freezers temperature control, mainly through the evaporation of heat exchanger copper tubes and condensation to achieve. The size and heat transfer performance of the heat exchanger tubes largely determine the efficiency and miniaturization of the entire air conditioning and refrigeration unit. In these machines, profiled copper tubes with high thermal conductivity are used. The use of steel's good processing performance, the development and production of heat pipes with internal grooves and high fins, used in the manufacture of air conditioners, freezers, chemical and waste heat mouth collection and other devices in the heat exchanger, the total heat transfer coefficient of the new heat exchanger can be increased to 2 to 3 times the ordinary tube, and with the ordinary low-finned tubes 1.2 to 1.3 times, has been used in the country, can save 40% of the copper, and make the heat exchanger volume Reduce the volume of heat exchanger more than 1/3.
Watch
Production of clocks and watches, timers and clock mechanism of the device, which most of the working parts are made of watch brass. The alloy contains 1.5-2% lead and has good machinability for mass production. For example, gears are cut from long extruded brass rods, flat wheels are punched from strips of the appropriate thickness, and brass or other copper alloys are used to make cradled clock faces, as well as screws and fittings. A large number of inexpensive watches were made of gunmetal (tin-zinc bronze) or plated with nickel-silver (white brass). Some famous clocks are made of steel and copper alloys. The hour hand of the British Big Ben is made of solid gunmetal rods, and the minute hand is made of 14-foot-long copper tubing.
A modern clock factory, using copper alloys as its main material and working with presses and precise molds, can produce 10,000 to 30,000 clocks a day at a fraction of the cost.
Paper Manufacturing
In our current society of ever-changing information, paper consumption is high. Paper may seem simple on the surface, but the papermaking process is complex, requiring the passage of many steps and the application of many machines, including coolers, evaporators, pulpers, paper machines, and so on. Many of these components, such as the various heat exchange tubes, rollers, striking bars, semi-liquid pumps and screens, are mostly made of steel alloys.
For example, the use of long net paper machine, it will make the pulp sprayed to the rapid movement of fine mesh (40 ~ 60 mesh) on the mesh. The mesh is woven from brass and phosphor-bronze wire, and it is very wide, typically 20 feet (6 meters) or more, and is required to be kept perfectly straight. The netting is moved over a series of small brass or copper rollers, and moisture is sucked out from underneath as it passes through with the pulp sprayed onto it. The web is simultaneously vibrated to bind the small fibers in the pulp together. Large paper machines have very large mesh sizes, up to 26 feet 8 inches (8. l meters) wide and 100 feet (3 0. 5 meters) long. Wet pulp not only contains water, but also contains chemicals used in the papermaking process, which are highly corrosive. In order to ensure the quality of paper, the mesh material requirements are very strict, not only to have high strength and elasticity; but also to resist pulp corrosion, copper alloy can be fully competent.
Printing
Printing with copper plate for photographic plate. Surface polished copper plate sensitized with photographic latex, photographic imaging on it. The sensitized copper plate needs to be heated to harden the rubber. In order to avoid softening by heat, copper often contains a small amount of silver or arsenic to improve the softening temperature. The plate is then etched to form a printing surface with a distribution of bumpy dot patterns.
To create the plate in an automatic typesetting machine, the plate is made by arranging brass font blocks, which is another important use of copper in printing. The font blocks are usually made of leaded brass, sometimes copper or bronze.
Medicine
Pharmaceutical industry, all kinds of steaming, boiling, vacuum devices are made of pure copper. In the medical equipment is widely used zinc white copper. Copper alloy is also a common material for eyeglass frames, etc. Recently discovered a number of higher critical temperature materials, called high-temperature superconducting materials, most of them are composite oxides. One of the earlier and better known ones is a lead-containing copper-based oxide (YB2 Cu3 O7), which has a critical temperature of 90 K and can be operated at liquid nitrogen temperatures. However, materials with critical temperatures near room temperature have not been obtained; moreover, these materials are difficult to make into large objects, and their ability to pass current densities that can maintain superconductivity is not high enough. Therefore, it has not been able to be used in strong electrical applications, pending further research and development.
Aerospace technology, rockets, satellites and space shuttles, in addition to microelectronic control systems and instrumentation, instrumentation equipment, many critical components also need to use copper and copper alloys. For example: the combustion chamber of the rocket engine and the inner village of the thrust chamber can be cooled by utilizing the excellent thermal conductivity of steel to keep the temperature within the permissible range. The combustion chamber lining of the Ariane 5 rocket, using copper a silver and a combination of gold, 360 cooling channels are machined within this lining, and liquid hydrogen is passed through to cool the rocket when it is launched.
Copper alloys are also a standard material for load-bearing components in satellite structures. The solar flaps on satellites are usually made of copper alloyed with several other elements.
Copper alloys are metallic materials.