What is copper

Copper is used by people in the form of a variety of metals, alloys and compounds. It has penetrated into all aspects of production and life, and has become an indispensable and important metal for the rapid development of human beings in the 21st century.

What is copper?

Copper is a metal element and also a transition element. The chemical symbol is copper, with atomic number of 29. Pure copper is a kind of soft metal. When the surface is cut, it is red and orange with metallic luster, and the elemental is purplish red. It has good ductility, high thermal conductivity and conductivity, so it is the most commonly used material in cables and electrical and electronic components. It can also be used as building materials and can form many kinds of alloys. Copper alloys have excellent mechanical properties and low resistivity, among which bronze and brass are the most important. In addition, copper is also a durable metal that can be recycled many times without damaging its mechanical properties.
Bivalent copper salt is the most common copper compound. Its hydrated ion is usually blue, while chlorine as ligand is green. It is the source of the color of minerals such as chalcopyrite and turquoise, and has been widely used as pigment in history. After the copper building structure is corroded, it will produce copper green (basic copper carbonate). Decorative arts mainly use metal copper and pigments containing copper.
Copper is one of the earliest metals used by human beings. As early as in prehistoric times, people began to excavate open-pit copper, and use the copper to make weapons, tools and other utensils. The use of copper has a far-reaching impact on the progress of early human civilization. Copper is a metal that exists in the earth’s crust and oceans. The content of copper in the crust is about 0.01%. In some copper deposits, the content of copper can reach 3% ~ 5%. Most of the copper in nature exists as copper ore.
The activity of copper is weak, and the reaction between iron and copper sulfate can replace copper. Copper is insoluble in non oxidizing acid.

The history of copper in ancient China

Copper and its alloys have been used for thousands of years. The main mining area of copper in ancient Rome was Cyprus, so it was named cyprium at first, and later became cuprum, which is the source of its English (copper), French (CUIVRE) and German (Kupfer).
Copper is one of the earliest metals used by human beings. As early as prehistoric times, people began to excavate open-pit copper, and use the copper to make weapons, implements and other utensils. The use of copper has a far-reaching impact on the progress of early human civilization.
China has a long history of using copper. About six or seven thousand years ago, Chinese ancestors discovered and began to use copper. In 1973, a semicircular remnant copper piece was unearthed from Jiangzhai site in Lintong, Shaanxi Province, which was identified as brass. In 1975, a bronze knife was unearthed from the Majiayao cultural site (about 3000 BC) in Linjia, Dongxiang, Gansu Province. It is the earliest bronze found in China and a proof of China’s entering the bronze age. Compared with West Asia, South Asia and North Africa, which entered the Bronze Age about 6500 years ago, China’s bronze age came later. There is a period of bronze and stone tools used together in China, about 5500-4500 years ago. On this basis, China invented bronze alloy, which is the same as the world bronze development model.
“The great event of the state lies in the sacrifice and military service.” For the Central Plains of pre Qin China, the biggest thing is sacrifice and foreign war. As a representative of the most advanced metal smelting and casting technology at that time, bronze was also mainly used in sacrificial rites and wars. The bronze wares discovered in Xia, Shang and Zhou dynasties all function as ceremonial utensils, weapons and accessories around them, which is different from the bronzes of other countries in the world and forms a bronze cultural system with Chinese traditional characteristics.
Generally speaking, the development of Chinese bronze culture can be divided into three stages, namely, the formation period, the heyday period and the transformation period. The formation period refers to the Longshan period, 4500-4000 years ago; the heyday refers to the Bronze Age of China, which includes Xia, Shang, Western Zhou, spring and autumn and the early Warring States period, lasting for more than 1600 years, that is, the bronze culture era of China’s traditional system; the transformation period refers to the end of the Warring States period, Qin and Han Dynasties, when bronze was gradually replaced by iron, not only in quantity, but also in quantity It has also changed from the original ritual and musical weapons and their use in important occasions such as rituals, sacrifices and war activities into daily utensils, and its corresponding types, structural characteristics and decorative arts have also undergone a turning point.

Formative period

The Longshan period, 4500-4000 years ago, is equivalent to the legend period of Yao, Shun and Yu. According to ancient documents, people began to smelt bronzes at that time. In the Longshan period sites in the middle and lower reaches of the Yellow River and the Yangtze River, through archaeological excavation, bronze products have been found in dozens of sites. According to the existing materials, the bronze wares of the formation period have the following characteristics

  • 1. Red copper and bronze coexisted, and brass appeared. A bronze knife was found in the Linjia site in Dongxiang, Gansu Province; two bronze plates with holes were found in the Dachengshan site in Tangshan, Hebei Province; a bronze container fragment containing 7% tin was found in the ganglongshan site in Dengfeng, Henan Province; a complete copper bell was found in the Taosi cemetery in Xiangfen, Shanxi Province; two brass cones were found in the Sanlihe site in Jiaoxian, Shandong Province; and the Yangjia site in Qixia, Shandong Province The circle unearthed fragments of brass. The Qijia culture in Gansu, Qinghai and Ningxia was found to have the largest number of copper products. Knives, cones, drills, rings and bronze mirrors were unearthed from several cemeteries. Some of them were bronze and some were red copper. In terms of production technology, some are forged and some are cast with molds, which are relatively advanced.
  • 2. There are few kinds of bronzes, most of which belong to daily tools and life, such as knives, cones, drills, rings, bronze mirrors, decorations, etc. But it should be admitted that people were able to make containers at that time. In addition, in Longshan culture, red or yellow pottery figurines are common, and there are imitative metal rivets in the mouth and abdomen. If we think that the bronze Figurine containers at this time have the same functions as the bronze Figurine containers in Xia and Shang Dynasties, the bronze vessels at that time have been or began to turn to ritual vessels.
  • 3. In general, small sites also unearthed bronze products, and the general residents also have bronze products. In addition, most of the bronze products in this period were simple and unadorned. Even the bronze mirrors with patterns were only geometric ornaments such as star stripes and triangle patterns, which had no mystery of the three generations of bronze ornamentation.


The heyday is the Bronze Age of China, including Xia, Shang, Western Zhou, spring and autumn and early Warring States period, which lasted for more than 1600 years. The bronzes of this period are mainly divided into ritual instruments, weapons and miscellaneous weapons. Musical instruments are also mainly used in the sacrificial activities of ancestral temples. Ritual utensils were used in ancient red tape rituals, either in temples, or for banquets and washing, and some were specially used for burial. Bronze ritual vessels have certain sacredness, which can not be used in ordinary life. Among all the bronzes, the number of ritual vessels is the largest and the production is the most exquisite. Ritual instruments can represent the highest level of Chinese bronze production technology. Ritual vessels include cooking utensils, food utensils, wine utensils, water utensils and statues. The bronzes of this period are the most exquisite in decoration and there are many kinds of ornaments.

Decoration of bronzes

One of the most common patterns on bronze ware is Taotie pattern, also known as animal face pattern. This kind of decoration first appeared on Liangzhu Culture jades in the lower reaches of the Yangtze River 5000 years ago, and Longshan Culture in Shandong inherited this kind of decoration. Taotie pattern, itself has a strong mystery. “Lu’s spring and Autumn Annals · Xianzhi” says: “Zhou Ding’s gluttonous eating is not only the first, but also the first without body Therefore, this kind of animal face pattern is generally called Taotie pattern. Taotie pattern has been used in bronze wares of Erlitou Xia culture. There are many types of Taotie patterns in Shang and Zhou dynasties, some like dragon, tiger, ox, sheep and deer, and others like bird, Phoenix and human. In the Western Zhou Dynasty, the mysterious color of bronze decoration gradually declined. Dragon and Phoenix are still the motif of many bronze patterns. It can be said that many patterned patterns are actually derived from dragon and snake and Phoenix.
Cicada pattern is a common pattern in Shang Dynasty and Western Zhou Dynasty. In the spring and Autumn period, there are also deformed cicada patterns. In the spring and Autumn period, the dragon pattern prevailed and gradually occupied the dominant position, almost crowding out other patterns. Another feature of Chinese bronzes is that no portrait has been found so far. Many bronzes use human faces as decorations, such as square tripod with human faces, Tomahawk with human faces, etc., but these human faces are not the faces of specific people. Most of the artifacts are the overall image of human beings, such as the lamp or pedestal of human beings, or the whole of human beings as a part of the artifacts, such as the bell stand with sword, the figure of human holding up the crossbeam, and the figure of several human feet under the copper plate. Most of these figures are the costumes of male and female attendants, and they are not the portraits of specific slaves. The three-dimensional images and human heads unearthed from Sanxingdui in Guanghan, Sichuan, are larger than those of normal people. They all have long ears, protruding eyes, high nose and wide mouth. They are full of mystery. They should be mythical figures.
Among the bronzes of Shang and Zhou dynasties, tens of thousands of bronzes have inscriptions, which are generally called gold inscriptions. For historians, it plays the role of proving and supplementing history.
Most of the inscriptions on Chinese bronzes are made by casting. The concave characters are called Yin characters, while the convex characters are called Yang characters. In the Shang Dynasty and the Western Zhou Dynasty, it can be said that the inscriptions were all cast. There are only a few examples of engraving with sharp tools.
In the late Western Zhou Dynasty, there began to appear inscriptions which were completely carved. In the middle of the Warring States period, most of the inscriptions were already carved. Even the three most classic ritual vessels in the Han Dynasty tomb of zhongshanwang in Pingshan, Hebei Province, were all carved in conjunction with each other. Their Sabre technique is extremely sophisticated and has high artistic value.
Another outstanding feature of ancient Chinese bronzes is the exquisite craftsmanship, which shows the ingenuity of ancient craftsmen. In ancient China, the method of making bronze wares with ceramic compound mould was fully developed. The selection of materials, mold turning and pattern engraving of pottery models are very exquisite, and the technology of Hun casting, separate casting, casting joint and stack casting is very mature. The subsequent development of wax loss process without separate casting is undoubtedly a great progress in bronze casting technology. The ancients believed that the bronzes were extremely strong and the inscriptions could be handed down for immortality, so the items to be handed down for a long time must be cast on the bronzes. Therefore, inscriptions have become an important material for the study of ancient history.
The technique of inlaying bronzes to increase their beauty has been around for a long time. The first kind of inlaid material is turquoise, which is still used in jewelry. The second kind is jade, which includes the spear of jade leaf, the axe of jade blade and so on. The third kind of meteorite iron, such as iron blade, copper Yue and iron aid copper blade, was identified as strong iron. The fourth is inlaid with red copper, which is used to form animal shaped patterns. In the spring and Autumn period and the Warring States period, bronzes were inlaid with gold and silver.

Smelting of bronzes

In the Eastern Zhou Dynasty, the development of smelting and casting technology was relatively high, and the technical summary document KAOGONGJI appeared. In the book, the proportion of copper and tin in bronze used for making various utensils, such as Bell and tripod, axe and Jin, Yi Ji, etc., is specified in detail. Due to frequent wars, weapon casting has developed rapidly. In particular, the swords of Wu and Yue are extremely sharp and famous all over the world. There are some famous swordsmen, such as Gan Jiang, Ou Zhizi and so on. Although some swords have been buried underground for more than 2000 years, they can still be cut into stacks of paper. The surface of some swords, such as the king of Yue’s Goujian sword, has been chemically treated to form anti rust diamond, scale or flame patterns, which are extremely gorgeous.

Transition period

The transformation period generally refers to the period from the end of the Warring States period to the end of the Qin and Han Dynasties. After hundreds of years of annexation war and political, economic and cultural reforms aimed at enriching the country and strengthening the army, the feudal society with centralized nature was finally established, the traditional etiquette system was completely collapsed, and iron products were widely used. Earth shaking changes have taken place in all fields of society.
The status of bronzes in social life is gradually declining. Most of the bronzes are daily-use, but as for some bronzes, there are still many exquisite works. For example, two bronze chariots and horses were excavated from Qin Shihuang mausoleum in Lintong, Shaanxi Province. The first is to drive four horses, with a shed on the car and the emperor sitting on it. These two horses are made of bronze castings, the size of which is in proportion to the actual situation, and they are extremely exquisite. There are a lot of gold and silver ornaments in the car, painted all over. The second chengma, 3.17 meters long and 1.06 meters high, can be said to be the largest and most complex bronze ware ever discovered.
By the end of the Eastern Han Dynasty, ceramics had been greatly developed and played an increasingly important role in social life, thus further excluding daily bronze utensils from life. As for weapons, tools and so on, iron had already occupied a dominant position. The bronze wares of Sui and Tang Dynasties are mainly all kinds of exquisite bronze mirrors with various inscriptions. Since then, apart from bronze mirrors, bronzes have no further development.

Physical and chemical properties of copper

Physical property

Copper is a purplish red metal with a density of 8.92 g / cm3. Melting point 1083.4 ℃, boiling point 2567 ℃. It’s very malleable. The thermal conductivity and conductivity are good.
Magnetism: diamagnetism
Crystal type: face centered cubic structure
Resistivity: 1.75 × 10-8 Ω· M
Sound speed (room temperature) 3810 (M / s)
Electrolytic copper crystal (very beautiful copper crystal can be obtained by electrolysis)
Electrolytic copper crystal (very beautiful copper crystal can be obtained by electrolysis) (19 pieces)
Young’s modulus: 110-128 GPA
Shear modulus: 48 GPA
Poisson’s ratio: 0.34
Mohs hardness: 3.0
Vickers hardness: 343 – 369 MPa
Brinell hardness: 235 – 878 MPa
Solid density 8.960 g / cm 3
The density of molten liquid is 8.920 g / cm 3
Specific heat capacity: 24.440 J / (mol · K)
Heat of vaporization: 300.4kj/mol
Melting heat: 13.26kj/mol
Thermal conductivity: 401 w / m.k
Expansion coefficient: (25 ° C) 16.5 μ M / m · K
The valence is usually + 2 or + 1 (trivalent copper occurs only in a few unstable compounds, such as potassium cuprate kcuo2)
Content in crust (PPM): 50
Content in the sun (PPM): 0.7
Ionization energy: 7.726 ev
The flame color is green.

Chemical property

Atomic size and structure
Electron layer: k-l-m-n
Electron layer distribution: 2-8-18-1
Electronic layout: 1s22s22p63s23p64s23d9
Atomic radius: 186pm
Van der Waals radius: 140pm
Reaction with oxygen

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Schematic diagram of copper atomic structure

Copper is a kind of inactive heavy metal, which does not combine with oxygen in dry air at room temperature. When heated, it can produce black copper oxide:

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If the temperature of Cu2O continues to be very high, the formation of Cu2O will occur:

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Reaction with air (reaction with O2, H2O, CO2)
After being exposed to humid air for a long time, a layer of copper green (basic copper carbonate) will be formed on the surface of copper. Copper Green can prevent further corrosion of metal, and its composition is variable.

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Copper has 29 isotopes. Cu-63 and Cu-65 are very stable, and their spin quantum numbers are 3 / 2.

Half life
Stable with 34 neutrons
12.700 hours
Stable with 36 neutrons
61.83 hours

The use of copper

Copper is a non-ferrous metal closely related to human beings. It is widely used in electrical, light industry, machinery manufacturing, construction industry, national defense industry and other fields. In China’s consumption of non-ferrous metal materials, copper is second only to aluminum. Copper is a red metal, but also a green metal. It is a green metal mainly because of its low melting point and easy remelting and remelting, so its recycling is quite cheap. In ancient times, it was mainly used for the casting of utensils, artworks and weapons. The more famous utensils and artworks include houmuwu Ding and Siyang fangzun.

Electrical and electronic market

The electrical and electronic market accounts for about 28% of the total. In 1997, these two markets became the second largest end users of copper consumption, with a 25% market share. In many electrical products (such as wire, bus, transformer winding, heavy motor, telephone line and telephone cable), the service life of copper is quite long. Only after 20 to 50 years, the copper in it can be recycled. The service life of other copper containing electrical and electronic products (such as small electrical and consumer electronic products) is relatively short, generally 5-10 years. Commercial electronic products and large electrical products are usually recycled because they contain precious metals besides copper. Nevertheless, the recovery rate of small consumer electronics products is quite low, because there is little copper in them.
With the rapid development of science and technology in the field of electronics, some old copper products are more and more out of date. For example, in the 1980s, telephone switching stations and central offices were the main sources of copper and copper alloy scraps, but the advent of digital conversion made these bulky, metal intensive things increasingly outdated.

Transportation equipment

Transportation equipment is the third largest market for copper, accounting for about 13% of the total, basically the same as in the 1960s. Although the importance of transportation has not changed, the use of copper has changed a lot. For many years, automatic radiators have been the most important end user in this area; however, the use of copper in automatic electrical and electronic products has grown rapidly, while the use of copper in the heat exchanger market has declined. The average service life of a car is 10-15 years, and almost all copper (including radiator and wiring) is recycled before its overall disassembly and recycling.

Industrial machinery and equipment

Industrial machinery and equipment is another major application market, in which copper often has a relatively long service life. Coins and ammunition are the main end users. Bullets are rarely recycled, some coins can be melted, and many are kept by collectors or savers and cannot be recycled. In the manufacturing of machinery and transport vehicles, it is used to manufacture industrial valves and accessories, instruments, sliding bearings, molds, heat exchangers and pumps.
In the chemical industry, it is widely used in the manufacture of vacuum, distillation pot, brewing pot and so on.
In the national defense industry, it is used to manufacture bullets, shells, gun parts, etc. for every 3 million bullets, 13-14 tons of copper are needed.
In the construction industry, it is used for various pipes, pipe fittings, decorative devices, etc.

Medical Science

In medicine, the bactericidal effect of copper has been known for a long time. Since the 1950s, copper has also been found to have very good medical uses. Later, Mexican scientists also found that copper has anti-cancer function. In the new century, British researchers have found that copper has a strong bactericidal effect. It is believed that copper will make a great contribution to improving human health in the near future.

Organic Chemistry

In organic chemistry, organic copper lithium compounds are a kind of important organometallic compounds.
Copper can be used to make many kinds of alloys. The important alloys of copper are as follows:

  • (1) Brass: brass is an alloy of copper and zinc, named for its yellow color. Brass has good mechanical properties and wear resistance. It can be used to manufacture precision instruments, ship parts, gun shells, etc. Brass sounds good, so gongs, cymbals, bells, trumpets and other musical instruments are made of brass.
  • (2) Nautical brass: an alloy of copper, zinc and tin. It is resistant to seawater erosion and can be used to make ship parts and balancers.
  • (3) Bronze: the alloy of copper and tin is called bronze, which is named for its green color. In ancient times, it was a common alloy (such as bronze age in China). Bronze generally has good corrosion resistance, wear resistance, castability and excellent mechanical properties. It is used for manufacturing precision bearings, high pressure bearings, marine anti seawater corrosion mechanical parts and various plates, pipes, bars, etc. Another unusual feature of bronze is “heat shrinkage and cold expansion”, which is used to cast statues. After cooling, they expand to make the eyes clearer.
  • (4) Phosphor bronze: an alloy of copper, tin and phosphorus. It is hard and can be used to make springs.
  • (5) Cupronickel: Cupronickel is an alloy of copper and nickel. Its color is the same as silver. Silver is shiny and not easy to rust. It is often used to make coins, electrical appliances, instruments and decorations.
  • (6) 18 K gold (rose gold): an alloy of 6 / 24 copper and 18 / 24 gold. It is red yellow and hard, and can be used to make jewelry and ornaments.

Copper smelting and production consumption

Copper ores extracted from copper ores are converted into copper concentrate with high copper grade or copper sand after beneficiation. Copper concentrate can only be refined copper and copper products after smelting. The earliest source of copper ore was malachite.

Processing of ore

Classification and properties of copper ores:
The raw material of copper smelting is copper ore. Copper ores can be divided into three categories:

  • (1) sulfide ores, such as cupies2, cu5fes4 and Cu2S, etc.
  • (2) oxidized ores, such as cuprite (Cu2O), malachite (Cu₂(OH)₂CO₃).
  • (3) natural copper. The copper content in copper ore is about 1% (0.5% ~ 3%) and it is valuable to exploit. Because flotation can remove some gangue and other impurities in the ore, and the concentrate sand with high copper content (8% ~ 35%) is obtained.
  • Smelting process of ore.

Copper smelting by fire

Cathode copper, or electrolytic copper, is produced by melting smelting and electrorefining. It is generally suitable for high-grade copper sulfide. In general, the pyrometallurgy is to raise the original ore containing a few percent or a thousand copper to 20% – 30% by beneficiation. As copper concentrate, matte smelting is carried out in closed blast furnace, reflector, electric furnace or flash furnace. The resulting matte (copper ice) is then sent to converter for converting to coarse copper, and then it is oxidized and refined to remove impurities in another type of reflecting furnace, or it is cast into anode plate for electric electricity The results show that the electrolytic copper with high grade of 99.9% is obtained. The process is short and adaptable, and the recovery rate of copper can reach 95%. However, sulfur in ore is discharged as sulfur dioxide waste gas in matte making and blowing stage, which is not easy to recover and cause pollution. In the 1990s, such as silver smelting, Nolanda smelting and Mitsubishi smelting in Japan, the smelting process gradually developed to continuous and automatic.
Copper smelting from copper ores: Taking chalcopyrite as an example, concentrate sand, flux (limestone, sand, etc.) and fuel (coke, charcoal or anthracite) are mixed, and put into “closed” blast furnace and smelted at about 1000 ℃. So, a part of sulfur in the ore becomes so Σ (used for sulfuric acid production), most of the impurities such as as as, Sb, Sb, O, etc. are removed: 2cufes Σ +o К = Cu Σ s+2fes+so К ↑. Some of the iron sulfide is transformed into oxide: 2fes + 3O Σ = 2FeO + 2SO Σ ↑. Cu ψ s and the remaining FES are melted together to form “ice copper” (mainly formed by the dissolution of Cu ψ s and FES, its copper content is between 20% and 50%, sulfur content is between 23% and 27%), and FeO and SiO Σ form slag: FeO + SiO Σ = fesio. Slag floating on the molten copper, easy to separate, to remove a part of impurities. Then, the copper ice was transferred into the converter, and the flux (quartz sand) was added to the converter and then the air was drum into the air for blowing (1100-1300 ℃). Because iron has a greater affinity for oxygen than copper and copper has a greater affinity for sulfur, the FES in ice copper is transformed into FeO first, and then it is slag formed by combining with flux, and then Cu ψ s is transformed into Cu Σ O. Cu ψ o reacts with Cu Σ s to generate coarse copper (copper content is about 98.5%). 2Cu Σ s+3o К = 2Cu Σ o+2so К ↑, 2cu∑o+cu Σ s=6cu+so К ↑, then move the coarse copper into the reflecting furnace, add the flux (quartz sand), and put in air to oxidize the impurities in the coarse copper, and form slag with the flux and remove it. After impurities are removed to a certain extent, they are injected into heavy oil. The reduction gases such as carbon monoxide produced by heavy oil combustion make cuprous oxide reduced to copper at high temperature. The copper content of the refined copper is about 99.7%.
In addition to copper concentrate, waste copper is one of the main raw materials for refining copper, including old and new waste copper. The old copper comes from old equipment and old machines, abandoned buildings and underground pipelines; new waste copper comes from scrap copper scrap (copper output ratio of copper is about 50%), and the general supply of waste copper is relatively stable, and waste copper can be divided into: bare copper: grade is more than 90%; yellow miscellaneous copper (electricity) Line: copper containing materials (old motors, circuit boards); copper produced by scrap copper and other similar materials, also known as recycled copper.

Hydrometallurgy of copper

A ship suitable for low-grade copper oxide, the production of fine copper is called electrowinning copper. Modern hydrometallurgy has sulfuric acid roasting leaching electrowinning, leaching extraction electrowinning, bacterial leaching, etc. it is suitable for heap leaching, tank leaching or in-situ leaching of low-grade complex ore, oxidized copper ore and waste copper ore. The wet smelting technology is being gradually promoted, and it is expected to reach 20% of the total production by the end of this century. The introduction of hydrometallurgy has greatly reduced the smelting cost of copper.

Common classification of copper

There are many people who think that copper is only one. It’s the only one. But there are other different types of copper. For example, alloy copper; brass is an alloy made up of copper and zinc; white copper is an alloy of copper and nickel; bronze is an alloy formed by copper and elements other than zinc and nickel, mainly tin bronze, aluminum bronze, etc.; copper with high copper content and other impurities is less than 1%.
Classification of copper processing materials: copper sulfate, copper chloride, copper bar, copper bar, copper ingot, copper plate, copper wire, copper alloy, coarse copper, copper strip, copper oxide, copper foil, copper tube, copper foil, copper mud, copper casting, electrolytic copper, other copper alloy copper.
All shapes made of pure copper or copper alloy include rod, wire, plate, strip, strip, tube, foil, etc. The processing of copper includes rolling, extrusion and drawing. The sheet and strip in copper have hot rolling and cold rolling; while strip and foil are cold rolled; pipe and bar are divided into extrusion products and drawn products; wire rod is drawn products.

Pure copper

Pure copper is a rose red metal, and the surface of copper oxide film is purple. Therefore, industrial pure copper is often called copper or electrolytic copper. The density is 8-9g / cm, melting point is 1083 ℃. Pure copper has good conductivity, and is widely used for manufacturing wires, cables, brushes, etc.; it has good heat conductivity, and is often used to manufacture magnetic instruments and instruments that need to prevent magnetic interference, such as compass and aviation instrument; it is of excellent plasticity and easy to be processed by hot pressing and cold force. It can be made into copper materials such as tubes, rods, wires, strips, strips, plates, foils and so on. There are two kinds of pure copper products: smelting products and processing products.
According to the composition, the processing materials of Chinese copper can be divided into four categories: ordinary copper (T1, T2, T3, T4), oxygen free copper (TU1, TU2 and high purity, vacuum oxygen free copper), deoxidized copper (TUP, tumn), special copper (as copper, tellurium copper, silver copper) with a small amount of alloy elements.
The conductivity and thermal conductivity of pure copper are second to silver, and are widely used in the manufacture of conductive and heat conducting equipment. Copper has good corrosion resistance in atmosphere, seawater and some non oxidizing acids (hydrochloric acid, dilute sulfuric acid), alkali, salt solution and many organic acids (acetic acid and citric acid), which are used in chemical industry. In addition, copper has good weldability, can be processed by cold and thermoplastic to make a variety of semi-finished products and finished products. In the 1970s, the output of copper exceeded the total output of other copper alloys.
The trace impurities in pure copper have a serious influence on the conductivity and thermal conductivity of copper. Among them, titanium, phosphorus, iron, silicon and so on significantly reduce conductivity, while cadmium and zinc have little influence. The solid solubility of oxygen, sulfur, selenium and Tellurium in copper is very small, which can produce brittle compounds with copper, which has little influence on conductivity, but it can reduce processing plasticity. When ordinary copper is heated in a reduced atmosphere containing hydrogen or carbon monoxide, hydrogen or carbon monoxide is easy to interact with copper oxide (Cu2O) at the grain boundary, which can produce high pressure water vapor or carbon dioxide gas, which can break copper. This phenomenon is often called the “hydrogen disease” of copper. Oxygen is harmful to the solderability of copper. The results show that the low melting point eutectic is formed between bismuth or lead and copper, which makes copper hot brittle, while brittle bismuth is thin film distributed at the grain boundary, and the copper will produce cold embrittlement. Phosphorus can significantly reduce the conductivity of copper, but it can improve the fluidity and weldability of copper liquid. Appropriate amount of lead, tellurium, sulfur and so on can improve the machinability.


Brass is an alloy of copper and zinc. The simplest brass is copper and zinc binary alloy, known as simple brass or ordinary brass. The brass with different mechanical properties can be obtained by changing the zinc content in brass. The higher the content of zinc in brass, the higher the strength and lower plasticity. The zinc content of brass used in industry is less than 45%, and the brittleness will be produced when the zinc content is higher, which will make the alloy properties worse. Brass can be divided into casting and pressure processing.
Brass is divided into two parts:
1) Brass
It is an alloy made of copper and zinc. When the zinc content is less than 39%, zinc can dissolve in copper to form single-phase a, called single-phase brass, which is of good plasticity and suitable for cold and hot pressing. When the zinc content is more than 39%, there are a single phase and B solid solution based on copper and zinc, called duplex brass. B makes the plasticity small and the tensile strength increases, which is only suitable for hot pressure processing.
The code is represented by “H + number”, h is brass, and the number indicates the mass fraction of copper. For example, H68 means brass with copper content of 68% and zinc content of 32%. For cast brass, the word “Z” before code, such as zh62, is used.
H90, H80 single phase, golden yellow, so there are gold altogether called, known as coating, ornaments, medals, etc. H68 and H59 are duplex brass, which are widely used in the structural parts of electrical appliances, such as bolts, nuts, washers, springs, etc.
In general, single phase brass is used for cold deformation processing and duplex brass for hot deformation processing.
2) Special brass
The multi alloy composed of other alloy elements added to the ordinary brass is called brass. The elements that are often added include lead, tin, aluminum, etc., which can be called lead brass, tin brass and aluminum brass accordingly. The purpose of adding alloy elements. The main purpose is to improve the tensile strength and improve the processability.
Code: it is indicated by “H + symbol of main plus elements (except zinc) + mass fraction of copper + mass fraction of main added element + mass fraction of other elements”.
For example: HPb59-1 indicates that the mass fraction of copper is 59%, the mass fraction of lead containing the main element lead is 1%, and the residual is zinc lead brass.


Bronze is the earliest alloy in history. It was originally copper tin alloy. It is called bronze because it is green gray. In order to improve the process and mechanical properties of the alloy, most bronze is also added with other alloy elements, such as lead, zinc, phosphorus, etc. Because tin is a rare element, many Wuxi bronze without Tin are used in industry. They are not only cheap but also have the special properties they need. Bronze is also divided into two categories: pressure processing and casting products.
Code: the representation method is composed of “q+ symbol of main plus element and mass score + mass score of other elements”. For casting products, the word “Z” is added before the code, for example, qal7 means 5% of aluminum, and the other aluminum bronze zqsn10-1 means that the tin content is 10%, the content of other alloy elements is 1%, and the residual is copper. Bronze can be divided into tin bronze and special bronze (i.e. Wuxi bronze).
(1) It is a copper tin alloy, also known as tin bronze, which is mainly added by tin
When the tin content is less than 5-6%, tin is dissolved in copper to form a solid solution, and the plasticity increases. When the tin content is more than 5-6%, the tin content of tin bronze is mostly between 3-14%, and when the tin content is less than 5%, it is suitable for cold deformation processing. When the tin content is 5-7%, it is suitable for thermal deformation processing. When the tin content is more than 10%, it is suitable for casting.
Because a is similar to the electrode potential and the tin nitriding in the composition produces dense tin dioxide film, the corrosion resistance of the film is increased, but the acid resistance is poor.
Because the temperature range of tin bronze is wide, the fluidity is poor, it is not easy to form concentrated shrinkage hole, but it is easy to form dendrite segregation and dispersion shrinkage hole. The casting shrinkage rate is small, which is conducive to the casting with close size to the casting mold, so it is suitable for casting with complex shape and large wall thickness, and it is not suitable for casting castings with high density and good sealing. Tin bronze has good friction reduction, anti-magnetic 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
Tin content is generally less than 8%. It is advisable to process the steel sections of plate, strip, rod and pipe under cold and hot pressure. After hardening, the tensile strength and hardness of the steel are increased and the plasticity decreases. After annealing, the plasticity can be improved, especially the high elastic limit can be obtained. The common ones such as corrosion resistant and wear-resistant parts, elastic parts, magnetic resistant parts, sliding bearings and shaft sleeves in the machine are commonly used in the instrument, such as qsn4-3qsn6.5-0.1.
B. Cast tin bronze
It is suitable for casting castings with complex shape but low density requirements, such as sliding bearing and gear, etc. The commonly used ones are zqsn10-1zqsn6-6-3.
2) Special bronze
The most special bronze has higher wear resistance and corrosion resistance than tin bronze, and the commonly used aluminum bronze (qal7qal5) lead bronze (zqpb30) and so on.
The copper base alloy with nickel as the main element is silver white, which is called white copper. The nickel content is usually 10%, 15%, 20%, the higher the content, the whiter the color. Copper nickel binary alloy is called ordinary copper, and copper nickel alloy with manganese, iron, zinc and aluminum is called complex white copper. Pure copper plus nickel can significantly improve strength, corrosion resistance, resistance and thermoelectric property. According to the performance and application, industrial copper can be divided into two types: structure copper and electrical white copper, which can meet various corrosion resistance and special electrical and thermal properties.

White copper

The copper base alloy with nickel as the main element is silver white, which is called white copper. Copper nickel binary alloy is called ordinary copper, and copper nickel alloy with manganese, iron, zinc and aluminum is called complex white copper. Pure copper plus nickel can significantly improve strength, corrosion resistance, resistance and thermoelectric property. According to the performance and application, industrial copper can be divided into two types: structure copper and electrical white copper, which can meet various corrosion resistance and special electrical and thermal properties.

Types of copper-nickel alloy

90-10 Copper and Nickel (C70600)

As the name suggests, this Marine alloy is 90 percent copper and 10 percent nickel. In addition, it also includes some elements in smaller parts, such as manganese and iron. These additional elements are important for improving corrosion resistance and overall strength.
In fact, manganese exists in this alloy as a desulfurizer and deoxidizer. Thus its presence enhances the working character. The combination of all the elements gives this alloy a high ductility and robustness. Again, it is clear that composition is what makes this alloy ubiquitous in a variety of industrial engineering, construction, and Marine applications. In brackish water and sea water, 90-10 white copper also provides excellent bio-fouling.
It also provides excellent manufacturing and welding properties and significantly resists embrittlement caused by hydrogen reactions.
In addition, the alloy also has high temperature retention and mechanical properties.
The C70600 is the most popular class and is popular in most places especially in the United States and Europe.
In most cases, this level is the most efficient when it involves industries such as shipbuilding, petrochemicals, offshore and Marine shipping.
They are also common in some cooling equipment and heat exchangers. This in itself is a testament to the quality and reliability provided by this particular class.
The 90-10 alloy has excellent antibacterial properties. Do you want to know what that means? Let me explain;
The copper-nickel grade has gone through some tests to prove its ability to kill a wide range of organisms in the shortest possible time.
It kills 99.9 percent of microbes, including influenza A, E. coli and methicillin-resistant Staphylococcus aureus, within two hours. For the record, an ideal manufacturer for this C70600 should be able to offer customized sizes and shapes of the product. Of course, this should depend on customer preferences.

70-30 copper and nickel (C71500)

Also, the name implies that copper and nickel are 70% and 30% respectively. Sometimes you can also refer to it as the C71500. It also contains additional elements of iron and manganese. These elements are essential to enhance the corrosion and erosion resistance of the alloy. The best part is that the strength level of 70-30 copper-nickel is relatively higher than that of 90-10. This is important, which is why it is more suitable for more demanding applications. This alloy is particularly resistant to corrosion in polluted high-speed water.
Another advantage of this material is that it is easy to cold work, weld and manufacture. All of this requires no special attention to materials. The most famous specifications covering this particular alloy include CN107 and C71500, which are another common reference for it. As I mentioned above, one of the outstanding features of 70-30 copper-nickel is its excellent corrosion resistance, especially in Marine areas. In addition, the material is resistant to biological contamination and has ideal strength and toughness. It has high impact pressure and medium machining properties. Therefore, it can be widely used in a variety of applications in the Marine environment, such as seawater piping.
In addition, it can also be used for pipe fittings, pump bodies, evaporator pipes and water tanks, etc.
In other cases, people use this copper-nickel alloy in oil and gas applications, where a moderate to high degree of seawater corrosion is present.

66-30-2-2 Copper-nickel alloy (C71640)

This is another grade of copper-nickel alloy that is also used in a wide range of applications. In some cases, it is called C71640 and has excellent corrosion resistance and corrosion resistance.
66-30-2-2 Cu-Ni alloys also have high antifouling properties, especially against microorganisms in water bodies.
In addition, it is easy to install and has good weldability. This particular alloy contains a high content of iron.
Now, this is beneficial because the iron content, in this case, helps to provide high ideal shock attack resistance.
In addition, 66-30-2-2 Cu-Ni has certain unique properties and can resist corrosion cracking. The best part of this alloyed copper is that it provides optimal service life even under the most adverse conditions.
In most cases, the alloy’s applications revolves around desalination plants, water heaters, coolers, condensers, refineries, petrochemical and shipbuilding distillations and repairs.

Copper nickel chrome

It is also an ideal copper alloy that you can use in a variety of applications. Basically, it’s a mixture of copper, nickel and chromium.
The combination alone will tell you the strength of the alloy and its resistance to various elements, such as corrosion and erosion.
In most cases, chromium is usually used to reduce the trace iron or a certain percentage of the iron content in such alloys.
So in fact, with the exception of a tiny amount of carbon and manganese, all of these elements combine to form stainless steel.
This is why this particular alloy has excellent corrosion resistance and corrosion resistance.
Similarly, it is used in a wide range of Marine applications, including distillation tubes in petrochemicals, desalination plants, oil refineries and water heaters.

High strength copper-nickel alloy

In many cases, the formation of high strength Cu-Ni alloys is often the result of the addition of aluminum to Cu-Ni.
The strength increases with the development of aging hardening precipitates.
This alloy is designed specifically to provide a unique blend of mechanical and physical properties for engineering with special properties.
At the same time, the alloy has excellent wear resistance and corrosion resistance, and has ideal properties for electrical and thermal components.
Another outstanding feature of this alloy is the absence of hydrogen embrittlement and the resistance to spark.
In addition, it provides ideal strength and hardness when you compare it with other non-ferrous alloys.
In addition, the alloy has low magnetic permeability and excellent low temperature properties.

Copper-nickel alloy for non-ship use

This is another type of copper-nickel alloy. As the name suggests, they mostly exist in applications that don’t necessarily revolve around naval Settings.
In most cases, they are used for a wide range of applications that do not match the Marine environment.
We have two main types of copper – nickel alloys for non – ship use. So let me say this briefly:

75-25 copper and nickel

This has been around for quite a long time since ancient times. It contains 75 percent copper and 25 percent nickel.
In most cases, it is used to make coins, which people often use in a wide range of trade activities.
This alloy exhibits some of the best properties, making it of very good quality. For example, it is resistant to corrosion.
Essentially, even under adverse conditions, it is difficult to find a 75-25 copper-nickel coin that corrodes.
Again, the alloy is relatively durable, lasting more than 30 years, but with the same quality.
Obviously, this is why this alloy is the preferred coinage, as it tends to circulate.
It’s also very malleable, which is why you’ll find portraits and other different images on the surface of coins.
In addition, the alloy is easy to press and recycle.

55 to 45 copper and nickel

The alloy contains 55% copper and 45% nickel, respectively. One of its outstanding features is its great resistance to the coefficient of low temperature.
It also has ideal resistivity. In fact, it is this particular aspect that makes 55-45Cu-Ni common in a variety of applications around thermocouples.
This is mainly because this resistivity property tends to be relatively constant over a wide range of temperatures.
Therefore, in general, all of these and other copper alloys not mentioned in this article are suitable for efficiency in a variety of applications.
You also need to be aware that some Marine alloys are not necessarily limited to Marine applications.
In fact, you’ll notice that quite a few of them are used in different non-marine applications.
For example, 90-10 copper-nickel is used for antimicrobial and brake tubes.

What is copper-nickel pipe fitting?

Copper-nickel pipe fittings are made of copper and nickel material and can be used to connect the Cu-Ni pipes to suit different applications. Their purpose is to ensure that the fluid is consistent and easy to flow through the piping system.
For the scope of this section, I will introduce you to the following copper-nickel fittings:

Copper nickel elbow

An elbow is useful when changing the direction of a pipe. Choose 90° or 45°, depending on the desired bending.
There are two kinds of copper – nickel elbow: short radius and long radius.
Remember, you can also choose to reduce the elbow. Normally, reducing elbows change not only the direction but also the pipe size.

Copper and nickel equal tee

Whenever fluid is collected or distributed in a piping system, a tee is required. Basically, it’s a small tube with a branch in the center — usually a 90° branch.
When using an equal tee, the diameter of the branch pipe is the same as that of the main pipe.

Cu-Ni reducing tee

This is another type of copper-nickel tee fitting. At this point, the diameter of the branch pipe is smaller than that of the main pipe.
Of course, there are other types of copper-nickel pipe tees, such as:

  • Lateral tee, branch pipe has some reinforcement welded to the piping system;
  • Y-tee with branch at 45° instead of 90°.

Copper nickel saddle

As with other pipe fittings, copper-nickel saddles come in a variety of shapes and designs. It all depends on the application at hand.

Copper and nickel stub end

In a copper-nickel piping system, sometimes you may want to completely cover one end of the piping. In this case, you need a copper-nickel stub end.

Copper and Nickel ASME B16.9 Short End

Copper-Nickel ASME B16.9 Short End is a special type of pipe fitting that you can use instead of soldering flanges, thus rotating the spare flange where necessary.
Sometimes, when you want to connect two copper-nickel tubes, you may need a flange. Copper-nickel flanges make it easier and faster to connect a variety of pipes, valves, pumps, or other components in a piping system.
Copper-nickel flanges are available in different shapes and designs depending on the type of piping system. Some of the most common options include:

As you can see, even if you buy the best copper-nickel tube, don’t forget to buy a suitable copper-nickel fitting too.

Source: China Pipe Fittings Manufacturer – Yaang Pipe Industry (www.steeljrv.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

If you want to have more information about the article or you want to share your opinion with us, contact us at sales@steeljrv.com

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