Brass

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Planispheric Astrolabe MET DP105325

Brass lectern in the form of an eagle attributed to Aert van Tricht the Elder, Limburg (Netherlands), c. 1500, The Cloisters

Microstructure of rolled and annealed brass; magnification 400X

Diagramme binaire Cu Zn

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00 BMA Automation Sampling cock

Brass is an alloy consisting primarily of copper, usually with zinc included. It is used for various applications due to its high malleability, durability, and resistance to corrosion. The proportions of zinc and copper can vary to create a range of brasses with varying properties; the addition of other elements such as lead or tin can produce alloys with improved machinability or strength.

History

The use of brass dates back to around the 3rd millennium BC in the Middle East, where it was initially used for decorative purposes and as a cheaper alternative to pure copper. Its production involved the co-smelting of copper ores with zinc ores. This process was refined over centuries, with significant advancements in the Roman Empire, where brass was used for coins, architecture, and military equipment.

Composition and Types

Brass is typically composed of 55% to 95% copper and 5% to 45% zinc. This variation in composition results in different types of brasses, each suited to specific applications. For example, Alpha brass (with less than 35% zinc) is ductile and used in forming processes, while Beta brass (with 45-50% zinc) is harder and suitable for casting.

Special Brass Alloys

• Lead Brass: Contains additional lead for improved machinability.
• Naval Brass: Has added tin for resistance to corrosion in seawater.
• DZR Brass: Dezincification resistant brass, used in water fittings to resist corrosion.

Properties

Brass has several desirable properties, including:

• Corrosion Resistance: Especially in marine environments, making it ideal for naval applications.
• Electrical Conductivity: Though less than copper, it is sufficient for electrical connectors and components.
• Thermal Conductivity: Good for heat exchangers and applications requiring heat dissipation.
• Machinability: Especially in leaded brasses, making it easy to shape and form.

Applications

Brass is used in a wide range of applications, from musical instruments like trumpets and trombones to plumbing and electrical components. It is also used in ammunition casings, architecture, and decorative items due to its gold-like appearance.

Environmental Impact

While brass is durable and recyclable, its production and processing can have environmental impacts, including the emission of greenhouse gases and the use of significant energy resources. Recycling brass is a critical component of reducing its environmental footprint.

See Also

• Copper
• Zinc
• Alloy
• Metal recycling