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 to make wires. Usually the wires used today are made of pure copper. This is because its electrical and thermal conductivity are second only to silver, but it is much cheaper than silver.
Common classification
Many people think that there is only one kind of copper. It is the only one. But there are other different kinds of copper. Such as alloy copper; brass is an alloy composed of copper and zinc; white copper is an alloy of copper and nickel; bronze is an alloy formed of copper and elements other than zinc and nickel, mainly tin bronze, aluminum bronze, etc.; red copper is Copper with a high copper content, the total content of other impurities is below 1%.
Classification of copper processing materials: copper sulfate, copper chloride, copper rods, copper bars, copper ingots, copper plates, copper wires, copper alloys, blister copper, copper strips, copper oxide, copper foil, copper tubes, copper foil, copper mud, Copper castings, electrolytic copper, and other copper alloy copper materials.
Various shapes including rods, wires, plates, strips, strips, tubes, foils, etc., are made of pure copper or copper alloys and are collectively referred to as copper. There are rolling, extruding and drawing methods for copper processing. Copper plates and bars are hot-rolled and cold-rolled; strips and foils are cold-rolled; pipes and bars are divided into For extruded products and drawn products; wires are all drawn products.
1 pure copper
Pure copper is a rose-red metal, and the surface is purple after a copper oxide film is formed. Therefore, industrial pure copper is often called red copper or electrolytic copper. The density is 8~9g/cm?, 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 commonly used to manufacture magnetic instruments and meters that must be protected from magnetic interference Such as compasses, aviation instruments, etc.; excellent plasticity, easy to heat and cold process, can be made into tubes, rods, wires, strips, strips, plates, foils, and other copper materials. There are two types of pure copper products: smelted products and processed products.
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 Four types of elemental special copper (arsenic copper, tellurium copper, silver copper).
The electrical conductivity and thermal conductivity of pure copper is second only to silver, and it is widely used in the production of electrical and thermal equipment. Red copper has good corrosion resistance in the atmosphere, sea water, certain non-oxidizing acids (hydrochloric acid, dilute sulfuric acid), alkali, salt solution and a variety of organic acids (acetic acid, citric acid), and is used in the chemical industry. In addition, red copper has good weldability and can be processed into various semi-finished and finished products through cold and thermoplastic processing. In the 1970s, the output of red copper exceeded the total output of other types of copper alloys.
The 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 conductivity, while cadmium, zinc, etc. have little effect. Oxygen, sulfur, selenium, tellurium, etc. have very low solid solubility in copper, 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, hydrogen or carbon monoxide can easily interact with cuprous oxide (Cu2O) at the grain boundary to produce high-pressure water vapor or carbon dioxide gas, which can crack the copper. This phenomenon is often called the "hydrogen disease" of copper. Oxygen is harmful to the weldability of copper. Bismuth or lead and copper form a low melting point eutectic, which makes copper hot and brittle; while brittle bismuth is distributed in the grain boundary in a thin film, it also makes copper cold and brittle. Phosphorus can significantly reduce the conductivity of copper, but it can increase the fluidity of copper liquid and improve solderability. An appropriate amount 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, called simple brass or ordinary brass. Changing the zinc content in brass can obtain brass with different mechanical properties. 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%. No matter how high the zinc content is, it will produce brittleness and deteriorate the properties of the alloy. Brass can be divided into 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 be dissolved in copper to form a single-phase a, called single-phase brass, which has good plasticity and is suitable for hot and cold press processing. When the zinc content is greater than 39%, there are a single-phase and copper-zinc-based solid solution b, which is called dual-phase brass. B makes the plasticity small and the tensile strength increases, which is only suitable for hot press processing.
The code is represented by "H+number", H represents brass, and the number represents the mass fraction of copper. For example, H68 means brass with 68% copper content and 32% zinc content; cast brass has a "Z" before the code, such as ZH62.
H90 and H80 are single-phase, golden yellow, so they are collectively called golden, called plating, decorations, medals, etc. H68 and H59 belong to two-phase brass, which are widely used in structural parts of electrical appliances, such as bolts, nuts, washers, springs, etc.
In general, single-phase brass is used for cold deformation and dual-phase brass is used for hot deformation.
2) Special brass
The multi-element 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. Mainly to improve the tensile strength and improve the processability.
Code: "H + symbol of the main element (except zinc) + mass fraction of copper + mass fraction of main element + mass fraction of other elements".
For example: HPb59-1 means that the mass fraction of copper is 59%, the mass fraction of lead is 1%, and the balance is lead brass with zinc.
3 bronze
Bronze is the earliest alloy used in history. It originally referred to copper-tin alloy. It was called bronze because of its bluish-gray color. In order to improve the process and mechanical properties of the alloy, other alloying elements, such as lead, zinc, and phosphorus, are added to most bronzes. Because tin is a scarce element, many non-tin-free Wuxi bronzes are still used in the 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 expression method is composed of "Q+main plus element symbol and mass score + mass score of other elements". For cast products, add the word "Z" before the code. For example: Qal7 means aluminum is 5%, the rest is copper aluminum bronze ZQsn10-1 means tin content is 10%, other alloying elements content is 1%, the balance is Cast tin bronze for copper. Bronze can be divided into two types: tin bronze and special bronze (namely Wuxi bronze).
(1) It is a copper-tin alloy with tin as the main element, also called tin bronze
When the tin content is less than 5 to 6%, tin dissolves in copper to form a solid solution, and the plasticity increases. When the tin content is greater than 5 to 6%, due to the presence of a Cu31Sb8-based solid solution, the tensile strength decreases, so tin bronze The tin content is mostly between 3-14%. When the tin content is less than 5%, it is suitable for cold deformation processing, and 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 similar to the electrode potential, and the tin in the composition is nitridated to form a dense tin dioxide film, the corrosion resistance of the atmosphere and seawater 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, and it is easy to form dendritic segregation and dispersed shrinkage cavities. The casting shrinkage rate is small, which is conducive to obtaining castings with a size very close to the mold, so it is suitable for casting The condition of complex shape and large wall thickness is not suitable for casting castings that require high density and good sealing. Tin bronze has good anti-friction properties, diamagnetism and low temperature toughness. According to the production method, tin bronze can be divided into two categories: pressure-processed tin bronze and cast tin bronze.
A, pressure processing tin bronze
The tin content is generally less than 8%, and it should be supplied by cold and hot pressure processing into plates, strips, rods, tubes and other profiles. After work hardening, its tensile strength and hardness increase, while plasticity decreases. After re-annealing, the plasticity can be improved while maintaining the higher tensile strength, especially the high elastic limit can be obtained. Corrosion-resistant and wear-resistant parts, elastic parts, anti-magnetic parts and sliding bearings in the machine, bushings, etc., are commonly used in suitable instruments. Qsn4-3Qsn6.5~0.1.
B. Casting tin bronze
Supplied by ingots, cast into castings by the foundry, suitable for castings with complex shapes but low density requirements, such as sliding bearings, gears, etc. The commonly used ones are ZQsn10-1 and ZQsn6-6-3.
2) Special bronze
Adding other elements to replace tin, or Wuxi bronze, most special bronzes have higher mechanical properties, wear resistance and corrosion resistance than tin bronze. Commonly used are aluminum bronze (QAL7QAL5), lead bronze (ZQPB30) and so on.
The copper-based alloy with nickel as the main additive element is silver-white and is called cupronickel. Nickel content is usually 10%, 15%, 20%, the higher the content, the whiter the color. The copper-nickel binary alloy is called ordinary cupronickel, and the copper-nickel alloy with elements such as manganese, iron, zinc and aluminum is called complex cupronickel. Pure copper and nickel can significantly improve strength, corrosion resistance, electrical resistance and thermoelectricity. Industrial copper-nickel alloys can be divided into structural copper-nickel alloys and electrical copper-nickel alloys according to their performance characteristics and uses, which meet various corrosion resistance and special electrical and thermal properties.
4 Cupronickel
The copper-based alloy with nickel as the main additive element is silver-white and is called cupronickel. The copper-nickel binary alloy is called ordinary cupronickel, and the copper-nickel alloy with elements such as manganese, iron, zinc and aluminum is called complex cupronickel. Pure copper and nickel can significantly improve strength, corrosion resistance, electrical resistance and thermoelectricity. Industrial copper-nickel alloys can be divided into structural copper-nickel alloys and electrical copper-nickel alloys according to their performance characteristics and uses, which meet various corrosion resistance and special electrical and thermal properties.
PUDA copper concentrate ton bag packing machine:
PUDA Design proposal for solving packing difficulties of copper concentrate powder
• Side wall angle of silo is more than 60 degrees to change contacting angle between silo and materials so as to avoid self bridge
• Wear-resisting and anticorrosion lining board of flow aid to prevent material adhesive to silo wall and avoid corrosion of materials to silo wall.
