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Bronze refers to a wide range of copper alloys with up to 10% tin as the main additive, but sometimes with other elements such as silicon, aluminum, manganese, or phosphorus. It’s tough, strong and has myriad uses in industries. It was especially important in antiquity, giving its name to the Bronze Age.
Today, bronzes are often stronger and more resistant to corrosion than brass. The variations in its composition significantly affect bronze’s characteristics. Corrosion-resistance, wearability, ductility for deep drawing and machinability are often considered. Parts made of bronze are normally used for clips, springs, electrical connectors and bearings.
Bronze is superior to iron in almost every application, with the exception of steel. Bronze doesn’t oxidize beyond the surface, even though it develops a patina. Bronze has a lower casting temperature and is considerably less brittle than iron. Copper-based alloys are more readily produced from their constituent metals and have lower melting points than steel. These alloys are normally about 10% heavier than steel, even though alloys using silicon or aluminum may be slightly less dense. Bronzes are weaker as well as softer than steel, and bronze springs are less stiff for the same bulk. However, it resists corrosion and metal fatigue better than steel and also conducts electricity and heat better than most steels.
Applications
Copper-based alloys have a wide range of uses that reflect their versatile mechanical, physical, and chemical properties. A few common examples are the resistance to corrosion by seawater of several bronze alloys, the resonant qualities of bell bronze, the low-friction properties of bearing bronze, the excellent deep-drawing qualities of cartridge case brass, and the high electrical conductivity of pure copper. In the 20th century, silicon was introduced as the primary alloying element. Silicon produced an alloy with many uses in industry and the major form used in contemporary statuary.
In addition, aluminum is also used as aluminum bronze for the structural metal. Bronze is the most popular metal for top-quality cymbals, bells as well as saxophones. It’s also used for cast metal sculptures. Bronze alloys usually have very desirable and unusual property of expanding slightly just before they set, thus filling in the finest details of a mold. Parts made of bronze are tough and often used for clips, bearings, springs, and electrical connectors. Bronze has little metal-on-metal friction. For this reason, it is invaluable for the building of cannons where iron cannonballs would otherwise stick in the barrel.
Today, it is widely used for bushings, springs, bearings, automobile transmission pilot bearings, and similar fittings, and is especially common in the bearings of small electric motors. In addition, phosphor bronze is especially suited for precision-grade springs and bearings. Bronze is usually 40% of tin and 60% of copper. Alpha bronze is made of the alpha solid solution of tin in copper. Blades, turbines, springs and cons are made of alpha bronze alloys of 4 to 5% of tin. Brass, which is also known as commercial bronze, is 10% zinc and 90% copper, and contains no tin.
Commercial bronze is stronger than copper and has equivalent ductility. It’s used for wires and screws. Unlike steel, bronze is non-sparking, which is another useful property of bronze. This means that it won’t generate sparks when struck against hard surface. This is used to advantage to make mallets, hammers, wrenches as well as other durable tools to be used in the presence of flammable vapors and in explosive atmospheres.
