What are the components of brass, bronze, copper and nickel silver?
Brass is an alloy composed 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.
Red copper is copper with a very high copper content, and the total content of other impurities is less than 1%.
1) Ordinary brass
It is an alloy composed of copper and zinc.
When the zinc content is less than 39%, zinc can dissolve in copper to form a single phase a, called single-phase brass, with good plasticity and suitable for hot and cold pressure processing.
When the zinc content is greater than 39%, there is a single phase a and a copper-zinc-based b solid solution, called dual-phase brass, b makes the plasticity small and the tensile strength increases, which is only suitable for hot pressure processing
If the mass fraction of zinc continues to increase, the tensile strength decreases and has no use value
The code is represented by "H + number", H represents brass, and the number represents the mass fraction of copper.
For example, H68 indicates brass with 68% copper content and 32% zinc content. For cast brass, "Z" is placed before the code, such as ZH62.
For example, Zcuzn38 indicates cast brass with 38% zinc content and the remainder copper.
H90 and H80 are single-phase and golden yellow, so they are collectively called gold, and are called plating, decorations, medals, etc.
H68 and H59 are duplex brass, which are widely used in structural parts of electrical appliances, such as bolts, nuts, washers, springs, etc.
Generally, single-phase brass is used for cold deformation processing and duplex brass is used for hot deformation processing.
2) Special brass
The multi-element alloy composed of other alloying elements added 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 tensile strength and processability
Code: "H + symbol of main added element (except zinc) + mass fraction of copper + mass fraction of main added element + mass fraction of other elements".
For example: HPb59-1 means lead brass with a mass fraction of 59% copper, a mass fraction of 1% lead as main added element, and the remainder is zinc.
2. Bronze
Except brass and white copper, the rest of the copper alloys are collectively called bronze, which can be divided into tin bronze and special bronze (i.e. Wuxi bronze).
Code: The representation method is composed of "Q + symbol and mass fraction of main added element + mass fraction of other elements". For cast products, "Z" is added before the code.
For example: Qal7 indicates aluminum bronze with 5% aluminum and the rest copper. ZQsn10-1 indicates cast tin bronze with 10% tin, 1% other alloying elements and the rest copper.
1) Tin bronze
It is a copper-tin alloy with tin as the main element, also known as tin bronze.
When the tin content is less than 5~6%, tin dissolves in copper to form a solid solution, and the plasticity increases. When the tin content is greater than 5~6%, due to the appearance of a solid solution based on Cu31sb8, the tensile strength decreases. Therefore, the tin content of tin bronze is mostly between 3~14%.
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 hot deformation processing. When the tin content is greater than 10%, it is suitable for casting.
Since the electrode potentials of a and & are similar, and the tin in the composition forms a dense tin dioxide film after nitridation, the corrosion resistance to the atmosphere and seawater increases, but the acid resistance is poor.
Because the crystallization temperature range of tin bronze is wide, the fluidity is poor, it is not easy to form concentrated shrinkage cavities, but it is easy to form dendrite segregation and dispersed shrinkage cavities, and the casting shrinkage rate is small, which is conducive to castings with sizes very close to the casting mold, so it is suitable for casting complex shapes. Thick wall conditions, but not suitable for castings requiring high density and good sealing.
Tin bronze has good friction reduction, antimagnetism and low temperature toughness.
Tin bronze can be divided into two categories according to the production method: pressure-processed tin bronze and cast tin bronze.
A. Pressure-processed tin bronze
The tin content is generally less than 8%, and it is suitable for cold and hot pressure processing into profiles such as plates, strips, rods, and tubes. After hardening, its tensile strength and hardness increase, while its plasticity decreases. After annealing, it can maintain high tensile strength and improve plasticity, especially obtain high elastic limit.
Suitable for instruments requiring corrosion resistance and wear resistance, elastic parts, anti-magnetic parts, and sliding bearings and sleeves in machines.
Commonly used ones are Qsn4-3 Qsn6.5~0.1.
B. Cast tin bronze
Supplied as ingots, cast into castings by the foundry, suitable for castings with complex shapes but low density requirements, such as sliding bearings, gears, etc. Commonly used ones are ZQsn10-1 ZQsn6-6-3.
2) Special bronze
Add other elements to replace tin, or tin-free bronze. Most special bronzes have higher mechanical properties, wear resistance and corrosion resistance than tin bronze. Commonly used ones are aluminum bronze (QAL7 QAL5) lead bronze (ZQPB30), etc.
Copper-based alloys with nickel as the main added element are silvery white and are called white copper. The nickel content is usually 10%, 15%, and 20%. The higher the content, the whiter the color. The copper-nickel binary alloy is called ordinary nickel silver, and the copper-nickel alloy with manganese, iron, zinc and aluminum is called complex nickel silver. Pure copper plus nickel can significantly improve strength, corrosion resistance, electrical resistance and thermoelectric properties. Industrial nickel silver is divided into structural nickel silver and electrical nickel silver according to different performance characteristics and uses, which meet various corrosion resistance and special electrical and thermal properties respectively.
