Brass
It was called "similor" to the alloy of copper and zinc in proportion 80 to 20; "Prince Albert metal" to the same alloy in the ratio 84 to 16; and "chrysocolla" to that of 82 parts of copper, 6 of zinc and 6 of tin.
Brass, according to the minority elements that intervene in the alloy, are malleable only when cold, and not when hot, and some are not so at any temperature. All types of this alloy become brittle when heated near the melting point.
Brass is harder than copper, but easy to machine, punch and melt, it is resistant to oxidation, saline conditions and is malleable, so it can be rolled into thin sheets.
Its malleability varies according to composition and temperature, and is different if it is mixed with other metals, even in minute quantities.
In lead brass, lead is practically insoluble in brass, and separates into fine globules, which favors chip fragmentation during machining.
Lead also has a lubricating effect due to its low melting point, which reduces wear on the cutting tool. Brass admits few heat treatments and only recrystallization and homogenization anneals are carried out.
Brass is an alloy of copper and zinc. The proportions of copper and zinc can be varied to create a variety of brasses with diverse properties. In industrial brass the percentage of zinc is always kept below 50%.
Its composition influences the mechanical characteristics, the fusibility and the formability by casting, forging, punching and machining.
When cold, the ingots obtained can be transformed into sheets of different thicknesses, rods or cut into strips that can be stretched to make wires. Its density also depends on its composition. In general, the density of brass is between 8.4 g / cm³ and 8.7 g / cm³. Its melting point is between 900 and 940 ° C, depending on the composition.
While bronze is instead primarily an alloy of copper with tin, some types of brass are referred to as 'bronzes'. Brass is a substitute alloy used for decoration because its luster gives it a similar appearance to gold, for applications where low friction is required, such as locks and valves, for plumbing and electrical applications, and, extensively, in musical instruments
such as trumpets and bells, as well as low cost cymbals (Power Beat, Paiste 101, 201 and in some quantities from the Pst series, Planet Z) for their acoustic properties.
Brass has been known to humans since prehistoric times, even before zinc itself was discovered. It was then produced by mixing copper with calamine, a natural source of zinc. In the German villas of Breinigerberg, an ancient Roman site, it was discovered where a calamine mine existed. During the mixing process, the zinc is extracted from the calamine and mixed with the copper. Pure zinc, on the other hand, has a very low melting point to have been produced by ancient metalworking techniques.
