collect! The most comprehensive copper industry knowledge in history!
Introduction: Copper is used by people in the form of a wide variety of metals, alloys and compounds, and has deeply penetrated into all aspects of production and life, becoming an indispensable and important metal for mankind to achieve rapid development in the 21st century.
Definition of copper
Copper is a chemical element, its chemical symbol is Cu, its atomic number is 29, and it is a transition metal. The most common use of copper is in the manufacture of wires. Usually the wires used today are made of pure copper because its electrical and thermal conductivity is second only to silver, but it is much cheaper than silver.
Common categories
Many people think that there is only one kind of copper. It is the only one. But there are actually other different types of copper. For example, alloy copper; brass is an alloy composed of copper and zinc; white copper is an alloy of copper and nickel; bronze is an alloy of copper and elements other than zinc and nickel, mainly including tin bronze, aluminum bronze, etc.; red copper is Copper with a high copper content, the total content of other impurities is less than 1%.
Categories of copper processing materials: copper sulfate, copper chloride, copper rods, copper bars, copper ingots, copper plates, copper wires, copper alloys, thick copper, copper strips, copper oxide, copper foil, copper tubes, copper foil, copper mud, Copper castings, electrolytic copper, other copper alloy copper materials.
Copper materials are made of pure copper or copper alloys into various shapes including rods, wires, plates, strips, strips, tubes, foils, etc. The processing of copper materials includes rolling, extrusion and drawing. Among copper materials, plates and strips are hot-rolled and cold-rolled; strips and foils are both cold-rolled; pipes and bars are divided into They are extruded products and drawn products; wire rods are all drawn products.
1 pure copper
Pure copper is a rose-red metal, which turns purple after a copper oxide film is formed on the surface. Therefore, industrial pure copper is often called red copper or electrolytic copper. The density is 8~9g/cm?, and the melting point is 1083°C. Pure copper has good electrical conductivity and is widely used in the manufacture of wires, cables, brushes, etc.; it has good thermal conductivity and is often used to manufacture magnetic instruments and meters that must be protected against magnetic interference. Such as compasses, aviation instruments, etc.; it has excellent plasticity and is easy to be hot-pressed and cold-processed. It can be made into copper materials such as copper tubes, copper rods, copper wires, copper bars, copper strips, copper plates, and copper foils. Pure copper products include smelted products and processed products.
China's red copper processing materials can be divided into: ordinary red copper (T1, T2, T3, T4), oxygen-free copper (TU1, TU2 and high-purity, vacuum oxygen-free copper), deoxidized copper (TUP, TUMn), adding a small amount of alloy There are four types of special copper elements (arsenic copper, tellurium copper, and silver copper).
The electrical conductivity and thermal conductivity of pure copper are second only to silver, and it is widely used in making electrical and thermal conductive equipment. Copper has good corrosion resistance in the atmosphere, seawater, certain non-oxidizing acids (hydrochloric acid, dilute sulfuric acid), alkali, salt solutions and various organic acids (acetic acid, citric acid) and is used in the chemical industry. In addition, red copper has good weldability and can be made into various semi-finished products and finished products through cold and hot plastic processing. In the 1970s, the output of red copper exceeded the total output of other types of copper alloys.
Trace impurities in pure copper have a serious impact on the electrical and thermal conductivity of copper. Among them, titanium, phosphorus, iron, silicon, etc. significantly reduce the electrical conductivity, while cadmium, zinc, etc. have little effect. The solid solubility of oxygen, sulfur, selenium, tellurium, etc. in copper is very small, and can form brittle compounds with copper, which has little effect on conductivity, but can reduce processing plasticity. When ordinary copper is heated in a reducing atmosphere containing hydrogen or carbon monoxide, the hydrogen or carbon monoxide easily interacts with the cuprous oxide (Cu2O) at the grain boundary to produce high-pressure water vapor or carbon dioxide gas, which can cause the copper to crack. This phenomenon is often called "hydrogen disease" of copper. Oxygen is harmful to the weldability of copper. Bismuth or lead forms a low melting point eutectic with copper, causing copper to become thermally brittle; and when brittle bismuth is distributed in a thin film at the grain boundaries, it causes copper to become cold brittle. Phosphorus can significantly reduce the conductivity of copper, but can increase the fluidity of copper liquid and improve weldability. Appropriate amounts of lead, tellurium, sulfur, etc. can improve machinability.
2 brass
Brass is an alloy of copper and zinc. The simplest brass is a binary alloy of copper and zinc, which is called simple brass or ordinary brass. Brass with different mechanical properties can be obtained by changing the zinc content in brass. The higher the zinc content in brass, the higher its strength and lower plasticity. The zinc content of brass used in industry does not exceed 45%. Any higher zinc content will cause brittleness and deteriorate the properties of the alloy. Brass can be divided into two categories: casting and pressure processing products.
Brass is divided into:
1) Ordinary brass
It is an alloy composed of copper and zinc. When the zinc content is less than 39%, zinc can dissolve in copper to form single-phase a, which is called single-phase brass. It has good plasticity and is suitable for hot and cold pressure processing. When the zinc content is greater than 39%, there is a single phase and a copper-zinc-based solid solution b, which is called dual-phase brass. b reduces the plasticity and increases the tensile strength, and is only suitable for hot pressure processing.
The code name is represented by "H + number", H represents brass, and the number represents the mass fraction of copper. For example, H68 means brass with a copper content of 68% and a zinc content of 32%; cast brass has a "Z" in front of the code, such as ZH62.
H90 and H80 are single-phase, golden yellow, so they are collectively called gold, and are called coatings, decorations, medals, etc. H68 and H59 are duplex brass, which are widely used in structural parts of electrical appliances, such as bolts, nuts, washers, springs, etc.
Generally, single-phase brass is used for cold deformation processing, and duplex brass is used for hot deformation processing.
2) Special brass
A multi-component alloy formed by adding other alloying elements to ordinary brass is called brass. Commonly added elements include lead, tin, aluminum, etc., which can be called lead brass, tin brass, and aluminum brass accordingly. The purpose of adding alloying elements. The main purpose is to increase the tensile strength and improve the workmanship.
Code: "H + symbol of the main plus element (except zinc) + mass fraction of copper + mass fraction of the main plus element + mass fraction of other elements".
For example: HPb59-1 means that the mass fraction of copper is 59%, the mass fraction of lead as the main additive element is 1%, and the balance is zinc.
3 bronze
Bronze is the earliest alloy used in history. It originally referred to copper-tin alloy. It is called bronze because of its bluish-gray color. In order to improve the process performance and mechanical properties of the alloy, other alloying elements such as lead, zinc, phosphorus, etc. are added to most bronzes. Since tin is a scarce element, many tin-free bronzes are still used in industry. They are not only cheap, but also have the required special properties. Bronze is also divided into two categories: pressure processing and casting products.
Code: The representation method is "Q + main plus element symbol and mass fraction + mass fraction of other elements". For cast products, the word "Z" is added before the code. For example: Qal7 means aluminum bronze containing 5% aluminum and the rest is copper. ZQsn10-1 means the tin content is 10%, the other alloying elements are 1%, and the balance is Copper cast tin bronze. Bronze can be divided into two categories: tin bronze and special bronze (i.e. Wuxi bronze).
(1) It is a copper-tin alloy composed of tin as the main plus element, also called tin bronze.
When the tin content is less than 5~6%, tin dissolves in copper to form a solid solution, and the plasticity increases. When the tin content is greater than 5~6%, the tensile strength decreases due to the emergence of a Cu31Sb8-based solid solution, so tin bronze The tin content is mostly between 3 and 14%. When the tin content is less than 5%, it is suitable for cold deformation processing. When the tin content is 5 to 7%, it is suitable for hot deformation processing. When the tin content is greater than 10%, it is suitable for casting.
Since a is close to the electrode potential, and the tin in the composition is nitrided to form a dense tin dioxide film, the corrosion resistance to atmosphere, seawater, etc. is increased, but the acid resistance is poor.
Because tin bronze has a wide crystallization temperature range and poor fluidity, it is not easy to form concentrated shrinkage cavities, but is prone to dendrite segregation and dispersed shrinkage cavities. The casting shrinkage is small, which is conducive to obtaining castings with dimensions very close to the casting mold, so it is suitable for casting. The conditions of complex shape and large wall thickness are not suitable for casting castings that require high density and good sealing. Tin bronze has good friction reducing properties, antimagnetic properties and low temperature toughness. According to the production method, tin bronze can be divided into two categories: pressure processing tin bronze and cast tin bronze.
A. Pressure processing tin bronze
The tin content is generally less than 8%, and it should be processed by hot and cold pressure into plates, strips, rods, tubes and other profiles. After work hardening, its tensile strength and hardness increase, but its plasticity decreases. After re-annealing, the plasticity can be improved while maintaining high tensile strength, especially obtaining a high elastic limit. For instruments that require corrosion-resistant and wear-resistant parts, elastic parts, anti-magnetic parts and sliding bearings and bushings in machines, Qsn4-3Qsn6.5~0.1 are commonly used.
B. Cast tin bronze
It is supplied as ingots and used in casting workshops. It is suitable for casting castings with complex shapes but low density requirements, such as sliding bearings, gears, etc. Commonly used ones are ZQsn10-1ZQsn6-6-3.
2)Special bronze
Add other elements to replace tin, or use tin-free bronze. Most special bronzes have higher mechanical properties, wear resistance and corrosion resistance than tin bronze. Commonly used ones include aluminum bronze (QAL7QAL5), lead bronze (ZQPB30), etc.
Copper-based alloys with nickel as the main added element are silvery white and are called white copper. The nickel content is usually 10%, 15%, 20%. The higher the content, the whiter the color. The copper-nickel binary alloy is called ordinary white copper, and the copper-nickel alloy with elements such as manganese, iron, zinc and aluminum is called complex white copper. Adding nickel to pure copper can significantly improve the strength, corrosion resistance, resistance and thermoelectricity. According to different performance characteristics and uses, industrial white copper is divided into two types: structural white copper and electrical white copper, which respectively meet various corrosion resistance and special electrical and thermal properties.
4 white copper
Copper-based alloys with nickel as the main added element are silvery white and are called white copper. The copper-nickel binary alloy is called ordinary white copper, and the copper-nickel alloy with elements such as manganese, iron, zinc and aluminum is called complex white copper. Adding nickel to pure copper can significantly improve the strength, corrosion resistance, resistance and thermoelectricity. According to different performance characteristics and uses, industrial white copper is divided into two types: structural white copper and electrical white copper, which respectively meet various corrosion resistance and special electrical and thermal properties.
How to identify
White copper, brass, red copper (also called "purple copper"), and bronze (blue-gray or gray-yellow) are distinguished by color. Among them, white copper and brass are easy to distinguish; red copper is pure copper (impurities <1%), and bronze (other alloy components are about 5%) is slightly difficult to distinguish. When not oxidized, the color of red copper is brighter than that of bronze, while bronze is slightly cyan or yellowish and darker; after oxidation, red copper turns black, while bronze becomes turquoise (harmful oxidation of too much water) or chocolate color.
Copper is the earliest metal used by human ancestors. It has many excellent characteristics and wonderful functions. It has not only made an indelible contribution to the progress of human society; it has also continuously developed new uses with the development of human civilization. Copper is both an ancient metal and a modern engineering material full of vitality. At present, mankind has entered a colorful and highly civilized society characterized by electrification and electronic information, which has opened up a broader land for the application of copper.
Why use copper, and what properties are it mainly used for? Copper has excellent electrical and thermal conductivity, ranking first among all engineering metal materials. This is the main basis for its pivotal role in the current electrification and electronic information society. Copper also has many excellent comprehensive properties: it has strong corrosion resistance to the atmosphere, seawater, soil and many chemical media; it is used in structures with both rigidity and softness, elasticity, friction resistance and wear resistance; it has colorful The appearance is a symbol of simplicity and elegance that people love. In addition to the above-mentioned numerous usability properties, it also has a series of good process properties such as processing, casting, welding, and easy cutting, making it economically and widely used.
--House construction accounts for 48%: including: pipeline systems (water, heat, gas, fire sprinklers, etc.); housing facilities (air conditioners, refrigerators, etc.); building decoration (roofs, launders, decorations, etc.); communication lines (sound , image, data, etc.); power supply system.
--Equipment production accounts for 41%: including: industrial equipment (motors, transformers, etc.); transportation (cars, railways, aircraft, etc.); electronic devices; light industrial products (household appliances, instruments, tools, etc.) - Basic facilities account for 11% %: Including: large-scale projects (transportation facilities, petrochemical industry, mining and metallurgy industry, etc.); electric power industry (power transmission, distribution, etc.); communication network.
It is worth noting that housing construction is directly related to the improvement of people's production level, and copper accounts for the largest proportion in this aspect; especially in my country, residential construction is an important link in stimulating the development of the entire national economy. It can be seen that active promotion The application of copper plays an important role in the national economy and people's livelihood.
A.Applications in the electrical industry
※ Power transmission
Power transmission requires a large amount of highly conductive copper, which is mainly used in power, cables, busbars, transformers, switches, plug components and connectors.
During the power transmission process of wires and cables, electrical 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. The "optimal cable cross-section" standard takes into account the two factors of one-time installation cost and power consumption, and appropriately enlarges the cable size to achieve energy saving and the best comprehensive economic benefits. According to the new standards, the cable cross-section is often more than double that of the old standards, which can achieve an energy saving effect of about 50%.
In the past period of time, due to the shortage of steel in our country, and considering that the proportion of aluminum is only 30% of copper, measures have been taken to replace copper with aluminum in overhead high-voltage transmission lines hoping to reduce weight. At present, for environmental protection reasons, aerial transmission lines will be converted to underground cables. In this case, aluminum pales in comparison to copper, which suffers from poor conductivity and larger cable sizes.
For the same reason, it is also a wise choice to replace the aluminum winding transformers in the United States and Japan with energy-saving and efficient copper winding transformers.
※ Motor manufacturing
In motor manufacturing, highly conductive and high-strength copper alloys are widely used. The main parts using copper are the stator, rotor and shaft head. 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 large length of hollow wire.
Motors are large consumers of electrical energy, accounting for approximately 60% of all electrical energy supply. The cumulative electricity bill for the operation of a motor is very high. It usually reaches the original cost of the motor within the first 500 hours of operation, which is equivalent to 4 to 16 times the cost within a year, and can reach 200 times the cost during the entire working life. A small increase in motor efficiency can not only save energy; it can also achieve significant economic benefits. The development and application of high-efficiency motors is a hot topic in the world. Since the energy consumption inside the motor mainly comes from the resistance loss of the winding; therefore, increasing the copper wire cross-section is a key measure to develop high-efficiency motors. Some high-efficiency motors that have been pioneered in recent years use 25 to 100% more copper windings than traditional motors. Currently, the U.S. Department of Energy is funding a development project to produce motor rotors using cast copper technology.
※ Communication Cable
Since the 1980s, due to its advantages such as large current-carrying capacity, optical fiber cables have continuously replaced copper cables on communication trunk lines and have been rapidly promoted and applied. However, converting electrical energy into light energy and connecting it to users still requires a large amount of copper. With the development of communications, people are increasingly dependent on communications, and the demand for optical fiber cables and copper wires will continue to increase.
※ Residential electrical wiring
In recent years, with the improvement of people's living standards in our country and the rapid spread of home appliances, residential electricity load has grown rapidly. Residential electricity consumption in our country will still develop greatly in the future, which will also greatly increase the application of copper wires.
B.Applications in the electronics industry
The electronics industry is an emerging industry. In its booming development process, new steel products and new products are constantly being developed.
