Many people know about bronze only that of itcast sculptures and monuments. In fact, this metal is deprived of popular attention undeservedly. Indeed, not for nothing in the history of mankind was even the Bronze Age - a whole era, during which the alloy held a dominant position. This is one of the few materials used both in industry and in art. The qualities possessed by the alloy of copper with tin are simply irreplaceable in many branches of production. It is used in the manufacture of guns, in machine building, in the casting of church bells, and so on. At the same time today there are a large number of metal brands, each of which has certain pre-modeled properties.
The first mention of the alloy of copper and tindate back to the 4th millennium BC. It is this technological breakthrough, according to historians, that allowed the civilization of Mesopotamia to occupy a leading position at that time. Archaeological excavations conducted in South Iran show the widespread use of bronze for the manufacture of arrowheads, daggers, spears, axes, swords. Among the finds there are even interior items, for example, furniture and mirrors, as well as pitchers, amphoras, vases and plates. For the coining of ancient coins and the manufacture of jewelry, the same alloy was used.
Bronze in the Middle Ages begins activelyused in Europe. It produces such massive objects as cannons and church domes. In a later period, with the development of machine building, so universal metal also did not go unnoticed. Its value was appreciated, mainly, for antifriction and anticorrosive properties. At the same time, it should be noted that the material used before was somewhat different from that which today is bronze. The composition of the alloy contained a number of minor impurities, significantly worsening its quality.
Today in material science bronze is called an alloytwo metals: copper and tin, which can be used in a variety of proportions. Zinc, phosphorus, magnesium, lead and silicon can be added to this metal to give the metal the specified qualities. The presence of random impurities with the help of modern technologies is practically reduced to zero.
In most cases, it is considered acceptablethe ratio of copper to tin in proportions of 85 to 15 percent. A decrease in the fraction of the second component below this level gives rise to a number of problems, the main of which is segregation. This term metallurgists call the process of stratification of the alloy and its uneven congealing.
Знающие люди могут много узнать о материале, лишь looking at the color that bronze possesses. The composition directly affects this parameter. It's not hard to guess, copper gives a red tinge to the alloy. Therefore, a decrease in its percentage ratio in favor of other components will mean a gradual transition of color to dimmer tones.
Что касается изменения практических характеристик alloy when experimenting with its composition, then the situation is as follows. The malleability of the material will depend directly on the content of tin in it. The smaller, the more pliable bronze, but this statement is true only to a certain limit. So, when the mark reaches 50%, the alloy again becomes soft.
A strong and durable materialthis low enough melting point and good malleability, could not help but interest creative people, in particular sculptors. Already in the 5th-4th centuries BC in Greece, the technology of making bronze statues was worked out to the smallest details, which is still relevant today.
For the production of guns, and later of other military equipment, bronze was always used. The composition of the alloy, which is used for these purposes, usually contains 90% copper and only 10% tin.
Колокольный звон обязан быть мелодичным, а его sound should please the hearing at a great distance. Ironically, Bronze has such musical talents. To improve the sound of the bell, it is made of an alloy with an increased content of tin (from 20 to 22%). Sometimes it also adds a little silver. Bronze grades, which are used in the manufacture of bells and other percussion instruments, are absolutely unsuitable for practical application in other industries. This is due to the fact that such an alloy has a fine-grained structure and increased brittleness.
For the first time an alloy consisting of 90% copper, 9% tin and1% of phosphorus was applied by Künzel in 1871. It was called phosphor bronze, and the material found its application mainly in engineering. Various parts of machines are cast from it, which are subject to increased friction. Phosphorus is necessary to increase the elasticity and increase the anti-corrosion properties. The main advantage of this metal is that it perfectly fills any grooves in the casting.
Aluminum bronze, whose composition is differenthigh content of copper (up to 95%), in appearance is very similar to gold. In addition to beauty, it has a number of other undeniable advantages. For example, the addition of 5% aluminum allows the alloy to withstand a long time exposure to an aggressive medium, such as increased acidity.
As a material for the manufacture of various partsmachines, this metal almost universally replaced phosphor bronze in paper mills and in powder production due to higher counteraction to the rupture.
Silicon is added to the alloy to enhanceelectrical conductivity. This is its quality used in the production of telephone wires. The reference composition of silicon bronze is as follows: 97.12% of copper, 1.14% of tin, 0.05% of silicon.
The most difficult process of obtainingboast an alloy with manganese content. The whole procedure goes through several stages. First, ferromangan is added to the molten copper. Then, having sustained the given temperature regime, tin is added, and, if necessary, zinc. The English company Bronce Company manufactures several grades of manganese bronze, which has different viscosity and hardness. This alloy can be used in virtually all industries.
