RICE
Brass is a copper-zinc alloy. The zinc ratio in an industrial alloy is at most 46%. Brass plating, a process based on depositing a thin layer of brass on the surface of a part by electrolysis. Brass is the most used copper alloy. History BC 51st century It extends to . In fact, in the times when zinc was not even known, this alloy was prepared by the method called “SEMENTATION”: Copper crumbs are heated in a crucible with zinc oxide (zinc carbonate ore calamine) and coal, the zinc formed by the reduction of the oxide is dispersed into the copper and usually 20% zinc molten alloy was obtained. The main advantages of brass are as follows: The feature of becoming sheet and wire enabling multi-shaped processing, mechanical resistance; resistance to the corrosive effect of the atmosphere; the ease of melting and casting and especially the low cost price due to the addition of zinc, which is a cheap metal. In addition, the brightness and color of some brasses change from red to pink with the use of these in jewellery, and turn yellow when the zinc ratio rises to 30-40%. The biggest feature of brass foundry is that zinc oxidizes very easily and emits white zinc oxide fumes; Therefore, it is necessary to protect the bathroom surface meticulously. According to its composition, rice is cold or hot processed: Brass with a zinc percentage of less than 10 (alpha phase) and more than 38 is usually hot processed; Brass with 10 to 38% zinc added changes shape in the cold (beta phase) • Ordinary brasses: Common brasses containing up to 20% zinc in their composition are used in jewellery and jewellery, to make small decorative pieces (Paris bronze, gold imitation, tombak, chrysocal). Those with a zinc percentage between 28 and 36 are malleable alloys; The most important of these is drawn brass (67-33), which is used in the manufacture of cartridge cases or lamp sockets. Chip removal brasses with a zinc content of 40 percent or more (60-40) . Usually 1% lead is added to these for easy machining in automatic machine tools.
