It is also because copper and silver tin oxide melt together to form an alloy, which has the same properties as the three. Because all three are soft, they are softer when they are combined. At this time, you can add some other substances to change its characteristics. Like carbon, titanium, silicon and other substances, it will not be soft. And the performance will get better and better.
Brass is harder than copper!
Pure copper, also called red copper, has a density of (7.83g/ cm3}) and a melting point of 1083 degrees. It is nonmagnetic and has good electrical and thermal conductivity, corrosion resistance and toughness.
The density of brass (8.93g/ cm3) is mostly used for mechanical bearing lining, which is wear-resistant.
Brass is denser than copper.
"Brass" hard
Brass is an alloy of copper and zinc.
White copper is an alloy of copper and nickel.
Bronze is an alloy of copper and elements other than zinc and nickel, mainly tin bronze and aluminum bronze.
Red copper is copper with high copper content, and the total content of other impurities is below 1%.
Ordinary brass
This is an alloy of copper and zinc.
When the content of zinc is less than 39%, zinc can be dissolved in copper to form single-phase A, which is called single-phase brass. Good plasticity, suitable for cold and hot pressing.
When the content of zinc is more than 39%, there are single phase and B solid solution mainly composed of copper and zinc, which is called biphase brass. B reduces plasticity and increases tensile strength, which is only suitable for hot pressing.
If the mass fraction of zinc continues to increase, the tensile strength will decrease and it is of no use value.
The code name is represented by "H+ number", H stands for brass, and the number represents the mass fraction of copper.
For example, H68 represents brass with copper content of 68% and zinc content of 32%, and adding "Z" before the symbol represents cast brass, such as ZH62.
For example, Zcuzn38 represents cast brass with zinc content of 38% and the rest copper.
H90 and H80 are single-phase and golden yellow, so they are called gold * * *, called electroplating, decorations, medals, etc.
H68 and H59 belong to biphase brass, which are widely used in the structural parts of electrical appliances, such as bolts, nuts, washers and springs.
Generally speaking, single-phase brass is used for cold deformation and double-phase brass is used for hot deformation.
2) Special brass
A multicomponent alloy composed of ordinary brass and other alloying elements is called brass. Usually added elements are lead, tin, aluminum and so on. , which can be called lead brass, tin brass and aluminum brass. The purpose of adding alloying elements. Mainly to improve tensile strength and manufacturability.
Code: it means "H+ symbol of main added elements (except zinc)+mass fraction of copper+mass fraction of main added elements+mass fraction of other elements".
For example, HPb59- 1 indicates that the mass fraction of copper is 59%, the mass fraction of lead containing main additive elements is 1%, and the rest is lead brass containing zinc.
2. Bronze
Except brass and white copper, other copper alloys are collectively called bronze, which can be divided into tin bronze and special bronze (Wuxi bronze).
Code: The representation method consists of "Q+ symbol of main added element and mass fraction+mass fraction of other elements". Add the word "z" before the code name of casting products.
For example, Qal7 represents aluminum bronze ZQsn 10- 1, with 5% aluminum and the balance copper, and represents cast tin bronze with 10% tin, 1% other alloying elements and the balance copper.
1) tin bronze
It is a copper-tin alloy with tin as the main element, also known as tin bronze.
When the content of tin is less than 5~6%, tin dissolves in copper to form a solid solution, and the plasticity increases. When the tin content is more than 5~6%, the tensile strength decreases due to the solid solution of Cu3 1sb8, so the tin content of tin bronze in the oxide scale 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 5~7%, it is suitable for hot deformation processing. When the tin content is greater than 10%, it is suitable for casting.
Because A and&; The electrode potential is similar, and the tin in the composition is nitrided to form a dense tin dioxide film, which improves the corrosion resistance to the atmosphere and seawater, but has poor acid resistance.
Due to the wide crystallization temperature range and poor fluidity of tin bronze, it is not easy to form concentrated shrinkage cavities, but easy to form dendritic segregation and dispersed shrinkage cavities, and the casting shrinkage rate is small, which is beneficial to obtain castings with sizes very close to the mold, so it is suitable for castings with complex shapes. The condition of large wall thickness is not suitable for castings with high density and good sealing.
Tin bronze has good antifriction, diamagnetism and low temperature toughness.
According to the production method, tin bronze can be divided into two categories: pressure processing tin bronze and casting tin bronze.
First, pressure processing tin bronze
The tin content is generally less than 8%, which is suitable for processing into plates, belts, bars, pipes and other profiles by cold and hot pressure. After work hardening, its tensile strength and hardness increase, while its plasticity decreases. After re-annealing, plasticity can be improved while maintaining high tensile strength, especially high elastic limit can be obtained.
Suitable for corrosion-resistant and wear-resistant parts, elastic parts, diamagnetic parts and sliding bearings and bushings in machines.
Commonly used are Qsn4-3 Qsn6.5~0. 1.
B, casting tin bronze
It is supplied by steel ingots and used by foundry to cast castings. Suitable for casting castings with complex shapes but low density requirements, such as sliding bearings and gears. Commonly used are zqsn10-1zqsn6-6-3.
2) Special bronze
Adding other elements instead of tin or Wuxi bronze, most special bronzes have higher mechanical properties, wear resistance and corrosion resistance than tin bronze, and commonly used are aluminum bronze (QAL7 QAL5) and lead bronze (ZQPB30).
The copper-based alloy with nickel as the main additive element is silvery white, which is called white copper. The content of nickel is usually 10%, 15% and 20%. The higher the content, the whiter the color. Copper-nickel binary alloy is called ordinary white copper, and copper-nickel alloy containing manganese, iron, zinc and aluminum is called complex white copper. Adding nickel to pure copper can significantly improve the strength, corrosion resistance, resistance and thermoelectric properties. Industrial white copper can be divided into structural white copper and electrical white copper according to different performance characteristics and uses, which meet various corrosion resistance and special electrical and thermal properties respectively.