Copper (Brass) classification & application fields

scanning:67 author:John Kino time:2019-11-09 classify:Industry News
Common classification: Brass is an alloy composed of copper and zinc. Copper is an alloy of copper and nickel. Bronze is an alloy of copper and elements other than zinc and nickel. It is mainly composed of tin bronze, aluminum bronze and other copper. Very high copper。

I. Common classification: Brass is an alloy composed of copper and zinc. Copper is an alloy of copper and nickel. Bronze is an alloy of copper and elements other than zinc and nickel. It is mainly composed of tin bronze, aluminum bronze and other copper. Very high copper,

The total content of other impurities is below 1%.

1, copper:

Copper is pure copper, also known as copper. The density of pure copper is 8.96 and the melting point is 1083 °C. It has good electrical conductivity and thermal conductivity, excellent plasticity, easy to be hot pressed and cold pressed, and is widely used in the manufacture of wires, cables, brushes, electro-etched copper for electric sparks and other products requiring good electrical conductivity.

Named after the purple color. It is not necessarily pure copper, and sometimes a small amount of deoxidizing elements or other elements are added to improve the material and properties, so it is also classified as a copper alloy. Chinese copper processing materials can be divided into: ordinary 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 Elemental special copper (arsenic copper, beryllium copper, silver copper) four categories.

The conductivity and thermal conductivity of copper are second only to silver and are widely used in the production of conductive and heat-conductive equipment. Copper is used in the chemical industry for its good corrosion resistance in the atmosphere, seawater and certain non-oxidizing acids (hydrochloric acid, dilute sulfuric acid), alkalis, salt solutions and various organic acids (acetic acid, citric acid). In addition, copper has good weldability and can be processed into various semi-finished products and finished products through cold and thermoplastic processing. In the 1970s, the output of copper exceeded the total output of other types of copper alloys.

Trace impurities in copper have a serious effect on the electrical and thermal conductivity of copper. Among them, titanium, phosphorus, iron, silicon, etc. significantly reduce the conductivity, while cadmium, zinc, etc. have little effect. Oxygen, sulfur, selenium, tellurium and the like have little solid solubility in copper, and can form brittle compounds with copper, which have little effect on conductivity, but can reduce processing plasticity. When ordinary copper is heated in a reducing atmosphere containing hydrogen or carbon monoxide, hydrogen or carbon monoxide easily interacts with grain boundary copper oxide (Cu2O) to generate high-pressure water vapor or carbon dioxide gas, which can rupture copper. This phenomenon is often referred to as the "hydrogen disease" of copper. Oxygen is detrimental to the weldability of copper.铋 or lead and copper form a low-melting eutectic, which makes the copper brittle; while the brittle is distributed in the film boundary, which makes the copper cold and brittle. Phosphorus can significantly reduce the conductivity of copper, but it can improve the fluidity of copper and improve weldability. Appropriate amounts of lead, antimony, sulfur, etc. can improve machinability.


2, brass

The copper alloy with zinc as the main additive element has a beautiful yellow color, collectively referred to as brass. The copper-zinc binary alloy is called ordinary brass or simple brass. Brass with more than three yuan is called special brass or complex brass. Brass alloys containing less than 36% zinc are composed of solid solution and have good cold workability. For example, brass containing 30% zinc is commonly used to make bullet casings, commonly known as cartridge brass or seven-three brass. Brass alloys containing between 36 and 42% zinc are composed of solid solution, the most common of which is 40% brass with 40% zinc. In order to improve the performance of ordinary brass, other elements such as aluminum, nickel, manganese, tin, silicon, lead, etc. are often added. Aluminum can improve the strength, hardness and corrosion resistance of brass, but it reduces the plasticity and is suitable for seawater condensing pipes and other corrosion resistant parts.

Tin can improve the strength of brass and its resistance to seawater. It is called naval brass and is used as a ship thermal equipment and propeller. Lead can improve the cutting performance of brass; this free-cutting brass is often used as a watch part. Brass castings are commonly used to make valves and pipe fittings.

The simplest brass is a copper-zinc binary alloy called simple brass or plain brass, which changes the zinc content of the brass to give brass with different mechanical properties. The higher the content of zinc in brass, the higher the strength and the lower the plasticity. The brass used in the industry does not contain more than 45% zinc. If the zinc content is high, brittleness will occur and the properties of the alloy will deteriorate.

Adding 1% tin to brass can significantly improve the resistance of brass to seawater and marine atmospheric corrosion, hence the name "Naval Brass". Tin can improve the cutting performance of brass. Lead brass is what we usually call the easy-to-cut copper.

The main purpose of lead addition is to improve machinability and improve wear resistance, and lead has little effect on the strength of brass. Engraving copper is also a type of lead brass. Most brass has good color, processability, and ductility, and is easy to plate or apply.

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 be dissolved in copper to form a single phase a, called single-phase brass, which is good in plasticity and suitable for cold and hot press processing. When the zinc content is more than 39%, there is a single phase and a copper-zinc based b solid solution, called duplex brass, b which makes the plasticity small and the tensile strength rises, and is only suitable for hot pressure processing. Code name

"H + number" means that H stands for brass and the number indicates the mass fraction of copper. For example, H68 means copper with a copper content of 68% and a zinc content of 32%. The cast brass is preceded by the "Z" code, such as ZH62. H90, H80 single phase, golden yellow, so there is a total of gold, called plating, decorations, medals and so on. H68 and H59 are duplex brass and are widely used in structural parts such as bolts, nuts, washers, springs, etc. In general, duplex stainless steel for cold deformation processing uses duplex brass for hot deformation processing.

2) Special brass A multi-component alloy consisting of other alloying elements added to ordinary brass is called brass. Commonly added elements are lead, tin, aluminum, etc., which may be referred to as lead brass, tin brass, aluminum brass. The purpose of adding alloying elements. Mainly to improve the tensile strength to improve the process. Code: Represented as "H + main plus element symbol (except zinc) + copper mass fraction + main plus element mass fraction + other element mass fraction". For example: HPb59-1 means that the mass fraction of copper is 59%, the mass fraction of lead with main additive element is 1%, and the balance is lead brass of zinc.

3, white copper

A copper alloy with nickel as the main additive element. The copper-nickel binary alloy is called ordinary white copper; the white copper alloy with elements such as manganese, iron, zinc and aluminum is called complex white copper. Industrial white copper is divided into two types: structural white copper and electrical white copper. Structural white copper is characterized by good mechanical properties and corrosion resistance, and beautiful color. This white copper is widely used in the manufacture of precision machinery, chemical machinery and marine components. Electrical white copper generally has good thermoelectric properties. Manganin, copper, and copper are manganese white copper with different manganese content. They are used in the manufacture of precision electrical instruments, varistor, precision resistors, strain gauges, thermocouples, etc.

4, bronze Originally referred to as copper-tin alloy, copper alloys other than brass and white copper are called bronze, and often preceded by the name of the first major additive element in the name of bronze. Tin bronze has good casting performance, anti-friction performance and good mechanical properties, and is suitable for manufacturing bearings, worm gears, gears, etc. Lead bronze is a widely used bearing material for modern engines and grinding machines. Aluminum bronze has high strength, good wear resistance and corrosion resistance, and is used for casting high-load gears, bushings, marine propellers, etc. Beryllium bronze and phosphor bronze have high elastic limit and good electrical conductivity, and are suitable for manufacturing precision springs and electrical contact components. Beryllium bronze is also used to manufacture non-sparking tools for use in coal mines and oil depots.

Because tin bronze has a wide temperature range and poor fluidity, it is difficult to form concentrated shrinkage cavities, and it is easy to form dendrite segregation and dispersion shrinkage. The casting shrinkage is small, which is advantageous for castings with dimensions very close to the mold, so it is suitable for casting. The shape is complicated. The condition of large wall thickness is not suitable for casting castings requiring high density and good sealing. Tin bronze has good friction reduction, diamagnetic resistance 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%. It should be processed into hot plate and plate, strip, rod, tube and other profiles. After work hardening, the tensile strength and hardness increase, and the plasticity decreases. After annealing, the plasticity can be improved at a higher tensile strength, in particular, a high elastic limit can be obtained. Applicable instruments require corrosion-resistant and wear-resistant parts, elastic parts, anti-magnetic parts and sliding bearings in machines, bushings, etc. Qsn4-3 Qsn6.5~0.1 is commonly used. B. Casting tin bronze is supplied by ingots and cast into castings by the foundry. It is suitable for casting castings with complex shapes but low density requirements, such as sliding bearings and gears. Commonly used are ZQsn10-1 ZQsn6-6-3.

2) Special bronze is added to other elements to replace tin, or is tin-free bronze. Most special bronzes have higher mechanical properties, wear resistance and corrosion resistance than tin bronze. Commonly used aluminum bronze (QAL7 QAL5) lead bronze ( ZQPB30) and so on. The copper-based alloy with nickel as the main additive element is silver white, which is called white copper. The nickel content is usually 10%, 15%, 20%, and the higher the content, the whiter the color. The copper-nickel binary alloy is called ordinary white copper. The copper-nickel alloy with manganese, iron, zinc and aluminum is called complex white copper. Pure copper plus nickel can significantly improve strength, corrosion resistance, electrical resistance and pyroelectricity. Industrial white copper is divided into two types: white copper for structure and white copper for electrician according to its performance characteristics and uses. It satisfies various corrosion resistance and special electrical and thermal properties. Second, distinguish: white copper, brass, red copper (also known as "copper"), bronze (blue or gray) is different in color.

Among them, white copper and brass are easy to distinguish; red copper is pure copper (impurities <1%), and bronze (about 5% of other alloy components) is slightly indistinguishable. When not oxidized, the red copper color is brighter than the bronze, the bronze is slightly cyan or yellowish; after oxidation, the red copper turns black, the bronze is greenish (the harmful oxidation of water) or chocolate.

Classification and welding characteristics of copper and copper alloys

(1) Pure copper: Pure copper is often called copper. It has good electrical conductivity, thermal conductivity and corrosion resistance. Pure copper is represented by the letter +T}} (copper), such as Tl, T2, T3, etc. The content of oxygen is extremely low, and is not more than 0. O1% of pure copper is called oxygen-free copper, and is represented by TU (copper no), such as TU1, TU2, and the like.

(2) Brass: A copper alloy with zinc as the main alloying element is called brass. Brass is represented by +H; (yellow) such as H80, H70, H68, and the like. (3) Bronze: The alloy of copper and tin was previously called bronze, and now the copper alloy other than brass is called bronze. Commonly used are tin bronze, aluminum bronze and sensitive bronze. Bronze is represented by "Q," (green).

The welding characteristics of copper and copper alloys are:

(1) refractory and easy to deform

(2) It is easy to generate hot cracks

(3) It is easy to produce pores. Copper and copper alloy welding mainly adopts gas welding, inert gas shielded welding, submerged arc welding, brazing and the like. Copper and copper alloys have good thermal conductivity, so they should be preheated before welding and welded with large wires. Tungsten hydrogen arc welding uses DC positive connection. For gas welding, copper uses a neutral flame or a weak carbonized flame, while brass uses a weak oxidizing flame to prevent the evaporation of zinc.

supplement:

1. The natural properties of copper Copper is one of the earliest ancient metals discovered by mankind. Humans began using copper as early as 3,000 years ago. Copper in nature is divided into natural copper, copper oxide ore and copper sulfide ore. Natural copper and copper oxide have low reserves. Now more than 80% of the world's copper is refined from copper sulphide ore. This ore contains very low copper, generally around 2-3%. Metallic copper, elemental symbol CU, atomic weight 63.54, specific gravity 8.92, melting point 1083Co. Pure copper is light rose or reddish. Copper has many valuable physicochemical properties, such as high thermal conductivity, strong chemical stability, high tensile strength, easy fusion, and corrosion resistance, plasticity, and ductility. Pure copper can be drawn into very thin copper wire to make a very thin copper foil. It can form alloys with metals such as zinc, tin, lead, manganese, cobalt, nickel, aluminum, iron, etc. The alloys formed are mainly divided into three categories: brass is a copper-zinc alloy, bronze is a copper-tin alloy, and white copper is a copper-cobalt-nickel alloy.

2. Copper smelting Copper ore mined from copper mines has been subjected to beneficiation to become copper concentrates with higher copper grades or copper ore. Copper concentrates need to be smelted to become refined copper and copper products.

A. Copper ore processing Copper used in the industry is electrolytic copper (containing 99.9% to 99.95% copper) and refined copper (containing 99.0% to 99.7% copper). The former is used in the electrical industry for the manufacture of special alloys, wires and wires. The latter is used to make other alloys, copper tubes, copper plates, shafts, and the like. a. Classification and properties of copper ore: The raw material for copper smelting is copper ore. Copper ore can be divided into three categories:

(1) Sulphide ore, such as chalcopyrite (CuFeS2), porphyrite (Cu5FeS4) and chalcopyrite (Cu2S).

(2) Oxidized ore, such as cuprite (Cu2O), malachite [Cu2(OH)2CO3], azurite [2CuCO3·Cu(OH)2], and chrysocolla (CuSiO3·2H2O).

(3) Natural copper. The content of copper in copper ore is about 1% (0.5% to 3%), which is worth mining. Because flotation can remove some impurities such as gangue in the ore, and the copper content is higher (8%). ~35%) of concentrate sand. b. Copper ore smelting process: The process of smelting copper from copper ore is more complicated. Taking chalcopyrite as an example, firstly, concentrate sand, flux (limestone, sand, etc.) and fuel (coke, charcoal or anthracite) are mixed and put into a "closed" blast furnace, which is smelted at about 1000 °C. Therefore, a part of the sulfur in the ore becomes SO2 (used to produce sulfuric acid), and most of the impurities such as arsenic and antimony are removed as volatile substances such as AS2O3 and Sb2O3: 2CuFeS2+O2=Cu2S+2FeS+SO2↑. A portion of the iron sulfide is converted to an oxide: 2FeS + 3O2 = 2FeO + 2SO2 ↑. Cu2S is melted together with the remaining FeS to form "ice copper" (mainly formed by the mutual dissolution of Cu2S and FeS, its copper content is between 20% and 50%, and the sulfur content is between 23% and 27%. Between) FeO and SiO2 form slag: FeO+SiO2=FeSiO3.

The slag floats on top of the molten copper and is easily separated to remove a portion of the impurities. Then, the matte is transferred into the converter, and a flux (quartz sand) is added, and then air is blown in for blowing (1100 to 1300 ° C). Since iron has a greater affinity for oxygen than copper, and copper has a greater affinity than iron for sulfur, the FeS in the matte is first converted to FeO, combined with flux to form slag, and then Cu2S is converted to Cu2O, Cu2O with Cu2S reacts to form blister copper (containing about 98.5% copper). 2Cu2S+3O2=2Cu2O+2SO2↑, 2Cu2O+Cu2S=6Cu+SO2↑, then move the blister copper into the reverberatory furnace, add flux (quartz sand), and let in air.

The impurities in the blister copper are oxidized and removed by forming a slag with the flux. After the impurities are removed to a certain extent, heavy oil is injected, and the reducing gas such as carbon monoxide generated by the combustion of the heavy oil reduces the cuprous oxide to copper at a high temperature. The obtained refined copper contains about 99.7% of copper. B. Copper smelting process The development of copper metallurgy technology has gone through a long process, but so far copper smelting is still dominated by fire rule-making, its output accounts for about 85% of the world's total copper production, and modern wet smelting technology is gradually Promotion, the introduction of wet smelting has greatly reduced the cost of copper smelting. Fire smelting and wet smelting (SX-EX).

a. Fire method copper smelting: Cathodic copper, that is, electrolytic copper, is produced by melt smelting and electrolytic fine smelting, and is generally suitable for high-grade copper sulfide ore. Pyrometallurgical smelting is generally carried out by adding a few or a few thousand of the original ore containing copper to 20-30% through beneficiation. As a copper concentrate, it is built in a closed blast furnace, reverberatory furnace, electric furnace or flash furnace.锍 smelting, the produced smelting (copper) is then sent to the converter for blowing into blister copper, and then oxidized and refined in another reverberatory furnace, or cast into an anode plate for electrolysis, and the grade is up to 99.9%. Electrolytic copper. The process is short and adaptable, and the recovery rate of copper can reach 95%. However, the sulfur in the ore is discharged as sulfur dioxide exhaust gas in the two stages of smelting and blowing, which is difficult to recycle and easily causes pollution. In recent years, there have been smelting of molten pools such as the silver method and the Noranda method, as well as the Mitsubishi method in Japan, and the smelting of pyrometallurgical gradualization has continued to be continuous and automated. The production process is roughly as follows: In addition to copper concentrate, scrap copper is one of the main raw materials for refined copper, including old scrap copper and new scrap copper. The old scrap copper comes from old equipment and old machines, abandoned buildings and underground pipelines. The new scrap copper comes from the copper scrap discarded by the processing plant (the output ratio of copper is about 50%). The supply of scrap copper is generally stable. The scrap copper can be divided into: bare copper:

Grade over 90%; yellow copper (wire): copper-containing materials (old motor, circuit board); copper produced from scrap copper and other similar materials, also known as recycled copper.

b. Wet copper smelting: A ship is suitable for low-grade copper oxide, and the produced refined copper is called electrowinning copper. Modern wet smelting has sulphation roasting-leaching-electrowinning, leaching-extraction-electrowinning, bacterial leaching, etc., suitable for low-grade complex ore, copper oxide ore, copper-containing waste ore heap leaching, tank leaching or Leaching. Wet smelting technology is gradually being promoted. It is expected to reach 20% of the total output by the end of the century. The introduction of wet smelting will greatly reduce the cost of copper smelting. The wet smelting process is:

c. Characteristics of the two methods of fire method and wet method Compared with the two methods of fire method and fire method, the following characteristics are obtained: (1) The latter smelting equipment is simpler, but the impurity content is higher, which is beneficial to the former. supplement. (2) The latter has limitations and is subject to the grade and type of ore. (3) The cost of the former is higher than the latter. It can be seen that the wet smelting technology has considerable advantages, but its scope of application has limitations. Not all smelting of copper mines can be used. However, through technological improvements, more and more countries in the past few years, including the United States, Chile, Canada, Australia, Mexico and Peru, have applied this process to more copper ore smelting. The improvement of wet smelting technology and the promotion of its application have reduced the production cost of copper, increased the production capacity of copper mines, increased the supply of social resources in the short term, and caused a relative surplus of total social supply, which has a pulling effect on prices.

3. Copper production and consumption a. Copper resource distribution: The world's copper resources are mainly distributed in North America, Latin America and Central Africa. At present, the world's proven reserves total 350 million tons, of which Chile accounts for 24%. The United States accounted for 16.9%, the CIS accounted for 10.15%, Zaire accounted for 7.39%, Zambia accounted for 4.55%, Peru accounted for 3.41%, and the Americas accounted for 60% of the world's reserves. China's copper production is concentrated in East China. The copper production in this region accounts for 51.84% of the country's total output, of which Anhui and Jiangxi provinces account for about 30%. The main consumption areas of copper are in East China and South China, and their consumption accounts for about 70% of the total national consumption. b. Main use of copper: Copper is a red metal and a green metal. It is said to be green metal, mainly because it is durable, easy to dissolve and re-smelt, so recycling is quite cheap.

In the 1960s, the largest market for copper was in the electrical and electronics markets, accounting for about 28% of the total. In 1997, these two markets became the second largest end-user of copper consumption, with a 25% stake. In many electrical products, (for example, wires, busbars, transformer windings, heavy-duty motors, telephone lines, and telephone cables) copper has a long service life, and only after 20 to 50 years, the copper inside can be recycled. . Other copper-containing electrical and electronic products (such as small appliances and consumer electronics) have a shorter life span, typically 5-10 years. Commercial electronics and large electrical products are usually recycled because they contain other precious metals in addition to copper. Despite this, the recovery rate of small electronic consumer products is still quite low, because there is almost no copper in them.

Classification and welding characteristics of copper and copper alloys

(1) Pure copper: Pure copper is often called copper. It has good electrical conductivity, thermal conductivity and corrosion resistance. Pure copper is represented by the letter +T}} (copper), such as Tl, T2, T3, etc. The content of oxygen is extremely low, and is not more than 0. O1% of pure copper is called oxygen-free copper, and is represented by TU (copper no), such as TU1, TU2, and the like.

(2) Brass: A copper alloy with zinc as the main alloying element is called brass. Brass is represented by +H; (yellow) such as H80, H70, H68, and the like. (3) Bronze: The alloy of copper and tin was previously called bronze, and now the copper alloy other than brass is called bronze. Commonly used are tin bronze, aluminum bronze and sensitive bronze. Bronze is represented by "Q," (green).

The welding characteristics of copper and copper alloys are:

(1) refractory and easy to deform

(2) It is easy to generate hot cracks

(3) easy to produce pores

Copper and copper alloy welding mainly uses gas welding, inert gas shielded welding, submerged arc welding, brazing and the like. Copper and copper alloys have good thermal conductivity, so they should be preheated before welding and welded with large wires. Tungsten hydrogen arc welding uses DC positive connection. For gas welding, copper uses a neutral flame or a weak carbonized flame, while brass uses a weak oxidizing flame to prevent the evaporation of zinc. Copper and aluminum welding Seamless flux cored wire is the latest technological achievement of aluminum-copper brazed joints, and is an upgraded product of aluminum-copper brazing materials. Its main component is composed of zinc aluminum copper and non-corrosive fluoroaluminum strontium salt. Its brazing processability, joint mechanical properties and joint conductivity are better than zinc cadmium and zinc tin copper brazing filler metal. Widely used in electric power appliances, information electronics, stainless steel products, refrigeration industry, electric appliances, hardware products and other industries. Environmentally friendly, convenient and safe aluminum-copper connections can be achieved without special welding equipment and special production sites. Among them, copper contains common copper alloys, and aluminum mainly refers to 1 series, 3 series and 6 series and part 4 series.

Zhengzhou Machinery Research Institute is currently the main domestic manufacturer of seamless core-cored aluminum welding wire. It has a history of more than 50 years of research on brazing materials and brazing processes. It is a member of the China Welding Society and the National Welding Standardization Committee. The copper-aluminum welding brazing filler metal has been matured in the copper-to-aluminum industry such as refrigeration, transformers, and motors. Distribution of world copper resources The world's copper resources are mainly concentrated in Chile, the United States, Zambia, Africa, Congo, Central and Eastern Canada, Russia and Peru. Among them, Chile is the country with the most abundant copper resources in the world, and its copper metal reserves account for about 1/4 of the world's total reserves. In terms of production, Chile is the world's largest copper producer, with production accounting for about 37% of global production in 2006. In terms of consumption, the European and European countries played a leading role in the copper consumer market before 2000, but after 2000, the protagonists of the copper consumer market were replaced by China, Russia, India and Brazil.

Types of Copper Brass Brass is an alloy of copper and zinc, named after the yellow color. Brass has good mechanical properties and wear resistance, and can be used to manufacture precision instruments, ship parts, and shells for guns. Brass knocks up and sounds good, so instruments such as cymbals, cymbals, bells, and numbers are made of brass. Nautical brass Copper alloy with zinc and tin, resistant to seawater erosion, can be used to make ship parts and balancers. Bronze The alloy of copper and tin is called bronze, which is named for its color. Bronze generally has good corrosion resistance, wear resistance, castability and excellent mechanical properties. It is used to manufacture precision bearings, high-pressure bearings, mechanical parts resistant to seawater corrosion on ships, and various plates, tubes, bars, etc. Bronze also has an anomalous property - "heat shrinking and cold expansion", which is used to cast a statue, and expands after cooling to make the eyebrows clearer. Phosphor Bronze Copper, an alloy of tin and phosphorus, is hard and can be spring-made.

White Copper White copper is an alloy of copper and nickel. Its color is the same as silver, and its silver is shiny and not easy to rust. Commonly used in the manufacture of electrical appliances, instruments and decorations.

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