Characteristics of copper and copper alloys

1. Good conductivity and thermal conductivity: Copper and its alloys have excellent conductivity and thermal conductivity, making them widely used in fields such as electronics, electrical, and communication.

2. Good plasticity and processability: Copper alloys have good plasticity and can be used to manufacture components of various shapes and sizes.

3. Good corrosion resistance: Copper alloys can maintain stability in various harsh environments.

4. Good strength and hardness: Copper alloys have high strength and hardness, and can be used to manufacture components that require strength and hardness.

5. Good heat resistance and wear resistance: Copper alloys have stable performance under high temperature, high pressure, high speed and other working conditions, and are suitable for manufacturing corresponding components. Especially for multi element copper alloy wear-resistant parts, shaft sleeves, bearing shells, turbines, etc. containing Sn.

6. Good antibacterial performance: Copper alloys have certain antibacterial properties and can be used to manufacture medical devices, food processing equipment, etc. Copper ions are released in aqueous media, which have the ability to inhibit bacterial and aquatic growth. Therefore, they are used in drinking water pipelines, washing machine cylinders, and propellers for ships.

7. Good electromagnetic shielding performance: Copper and certain copper alloys can block the propagation of electromagnetic waves. Extremely low magnetic susceptibility, used in compass, radar and other anti external magnetic field environments.

8. Environmentally friendly materials: Some copper alloys are non-toxic and can be used to manufacture parts that come into contact with food.

9. Economy: Copper alloys have relatively low prices and are suitable for large-scale applications.

Classification of copper and copper alloys

1. Pure copper, also known as purple copper, is often used for static sealing of pipelines in vacuum sealing due to its highest copper content, purity greater than 99.5%, good ductility and flexibility.

2. Copper alloys are divided into brass (ordinary brass, special brass), bronze (tin bronze, aluminum bronze, beryllium bronze, silicon bronze, lead bronze), and white copper (ordinary white copper, special white copper).

Pure copper is divided into ordinary pure copper, deoxygenated copper, anaerobic copper, and special copper according to the amount of other elements it contains. Has excellent thermal conductivity, conductivity, non-magnetism, and plasticity. It has good corrosion resistance in the atmosphere and fresh water, but poor in seawater.

Ordinary pure copper: With high oxygen content, it cannot be heated in reducing media to avoid hydrogen embrittlement. It is mainly used for conductive and thermal conductive components.

Deoxygenated copper: residual deoxidizer elements (P, Mn) seriously reduce the conductivity of copper and should only be used as structural materials.

Oxygen free copper: with extremely low oxygen and impurity content, it is mainly used in electric vacuum devices.

Special copper: containing different trace specific elements, such as As, Ag, Te, and dispersed copper, mainly used in conductive structural components.

The characteristics of brass

Brass is divided into ordinary brass and special brass.

Ordinary brass: generally only contains two elements, such as Cu Zn binary alloy. H68 represents a copper zinc alloy containing 68% Cu.

When corrosion occurs, zinc is corroded (galvanized), therefore it has good corrosion resistance. The higher the zinc content, the cheaper it is, up to 46%;

The higher the zinc content, the greater the risk of stress corrosion cracking. However, the addition of Si and As can reduce the risk of such rupture.

73 brass, also known as shell brass, is made of H70 and is commonly used in the manufacture of shell casings.

Eryi brass contains about 65% copper and can be used to manufacture copper rods, wires, sheets, pipes, wooden screws, springs, etc.

The 64 brass contains about 60% copper and is commonly used in the manufacture of heating pipes, copper sheets, copper wires, copper rods, etc.

The commonly used brass models for non-standard design include H57, H59, H62, H65, H68, etc., each with different characteristics:

H57 brass: has good plasticity and corrosion resistance, suitable for making thin-walled parts and complex shaped products.

H59 brass: High strength, good corrosion resistance, suitable for making parts or products that require certain strength and corrosion resistance.

H62 brass: It has high strength and hardness, good wear resistance, and is suitable for making parts or products that need to withstand large loads.

H65 brass: It has good corrosion resistance and strength, as well as a certain degree of toughness, and is suitable for making parts or products that need to withstand certain impacts and vibrations.

H68 brass: With high strength and hardness, as well as good corrosion resistance and toughness, it is suitable for making parts or products that need to withstand large loads and certain impacts and vibrations.

Special brass: a variety of alloys composed of two or more elements.

Aluminum brass: Aluminum can improve the strength, hardness, and corrosion resistance of brass, but at the same time, it can also reduce its plasticity, making it suitable for use in marine condenser tubes and other parts that require corrosion resistance.

Tin brass: Tin can improve the strength and corrosion resistance of brass to seawater, and is commonly used in the manufacture of ship thermal equipment and propellers. However, it should be noted that the tin content in tin brass usually ranges from 0.5% to 1.5%, and excessive tin can be detrimental to the plastic deformation of the alloy. Commonly used tin brass includes HSn70-1, HSn62-1, and HSn60-1.

Lead brass: Lead can improve the cutting performance of brass, so it is commonly used in the manufacturing of precision machined parts such as clocks and watches.

Manganese brass: Manganese element has a high solubility in solid brass. When 1% to 4% manganese is added to brass, the strength and corrosion resistance of the alloy can be significantly improved without reducing its plasticity.

Iron brass: Iron can improve the mechanical and process properties of brass. The commonly used iron brass plate number is Hfe59-1-1, with an iron content usually below 1.5%, which has high strength and toughness.

Nickel brass: Nickel can significantly improve the corrosion resistance of brass in the atmosphere and seawater.

The characteristics of bronze

Bronze is an ancient metal alloy that can be divided into various types based on its composition, such as tin bronze (commonly used), aluminum bronze, beryllium bronze, phosphorus bronze, silicon bronze, etc.

Tin bronze is widely used in our daily lives, containing 3-14% tin. As the tin content increases, the strength and hardness of the alloy will also correspondingly improve. This alloy has a small volume shrinkage rate and better corrosion resistance than both copper and brass.

When the tin content is less than 6%, it is suitable for cold deformation processing;

When the tin content is between 6-7%, it is suitable for hot processing;

When the tin content is between 10-14%, it is suitable for casting alloys.

Multi element tin bronze refers to the addition of elements such as zinc, phosphorus, lead, nickel, etc. to tin bronze, which can effectively improve the mechanical properties of alloys, especially the elastic and fatigue limits. Therefore, it is commonly used in the production of springs.

Commonly used tin bronze such as QSn4-3, QSn6.5-0.4, ZCuSn10Pb1, etc., due to their good mechanical properties and corrosion resistance, are often used to manufacture elastic components, wear-resistant parts, anti magnetic and corrosion-resistant parts, such as springs, bearings, gears, turbines, washers, etc.

Mechanical tin bronze, also known as gun copper, contains 10% tin and is often used to make corrosion-resistant and wear-resistant components such as gears, valves, and propellers.

Tin bronze bearings contain 12-15% tin and are commonly used to make low-speed heavy-duty bearings such as railway axles.

Coin tin bronze contains 4-10% tin, with good ductility and excellent castability, commonly used in coin making.

Bell bronze contains 20-32% tin, and the less impurities there are, the clearer and more pleasant the sound.

Bronze ware is an ancient type of copper product, mainly composed of copper and tin, sometimes with elements such as zinc and lead added. The bronze used for bronze statues and home decorations is added with a small amount of nickel and arsenic to improve the fluidity of the solution and make the surface patterns of the castings clear.

In ancient times, mirrors were made of copper, known as mirror copper, which consisted of two-thirds of copper and one-third of tin.

The aluminum content of aluminum bronze is less than 11.5%. Due to the higher price of tin compared to aluminum, people often replace some tin bronze with aluminum bronze.

In terms of casting performance, aluminum bronze has good fluidity, but has a large volume shrinkage rate and contains alumina inclusions, making it prone to cracking.

In terms of mechanical performance, aluminum bronze does not produce sparks. As the aluminum content increases, strength and hardness will increase, but plasticity will decrease.

When the aluminum content is between 5-8%, both cold and hot processing can be carried out; When the aluminum content is between 8-11%, the flowability is poor, so it is often used as a casting alloy.

In terms of corrosion resistance, the surface of aluminum bronze will form a dense oxide film, so its corrosion resistance is better than that of tin bronze.

Multi element aluminum bronze refers to the addition of elements such as iron, nickel, and manganese to aluminum bronze. The addition of these elements can refine the grain size, avoid spontaneous tempering brittleness, improve strength, and avoid tempering brittleness. Meanwhile, nickel can also improve heat and corrosion resistance.

Beryllium bronze is a very precious metal material, and its price is even higher than silver. This metal material has high strength, high hardness, and excellent fatigue and elastic limits. It also has excellent corrosion resistance, wear resistance, and cold resistance, and will not react in acidic or alkaline environments. In addition, beryllium bronze also has good conductivity and thermal conductivity.

Beryllium bronze is often used as advanced precision elastic components and special wear-resistant components. It is also often used in impact free environments such as mines and refineries. In order to further improve the performance of beryllium bronze, a small amount of Ni is usually added, which can improve elasticity, strength, wear and corrosion resistance.

When making beryllium bronze, it is also necessary to control the content of impurity elements P and Pb to avoid affecting the material properties.

The characteristics of white copper

According to chemical composition, white copper can be divided into ordinary white copper and special white copper.

Ordinary white copper is composed only of copper and nickel.

In addition to copper and nickel, special white copper also contains elements such as zinc, manganese, aluminum, iron, and lead, hence it is called zinc white copper, manganese white copper, aluminum white copper, iron white copper, and lead white copper.

White copper can be divided into structural white copper and electrical white copper according to their uses.

Structural white copper refers to Cu Ni alloy with high strength and corrosion resistance, usually containing 3-30% Ni, and is often used as a structural material under high pressure and low temperature.

Electrical white copper has excellent conductivity and elongation, making it suitable for making long span, high strength transmission lines and overhead electric wires.

Special white copper is based on structural white copper by adding other elements to improve its performance.

For example, aluminum white copper has excellent high-temperature performance and is suitable for use in high-temperature parts of internal combustion engines;

Silicon white copper has excellent elongation and conductivity, making it suitable for use in high-strength span transmission lines, overhead tram lines, etc;

Zinc white copper has excellent heat resistance, corrosion resistance, and fatigue resistance, with a small resistance temperature coefficient, making it suitable for making springs or thermoelectric materials.

Structural white copper includes ordinary white copper, iron white copper, zinc white copper, and aluminum white copper, which have good corrosion resistance and processing performance. Used for making condensers, heat exchangers, medical devices, corrosion-resistant parts, artworks, etc.

Electrical white copper includes ordinary white copper and manganese white copper, which have high resistance, high thermoelectric potential, and low resistance temperature coefficient. It is used for compensating wires, thermocouples, resistance instruments, and heaters.

Article source: Xiaoyao Pot

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