Definition - What does Brass mean?
Brass is a non-ferrous, red metal and an alloy that is composed of copper and zinc. The proportions of copper and zinc can be varied in order to achieve different desired mechanical and electrical properties. Brass contains atoms of the two constituent elements that may replace each other within a single crystalline structure, and hence is referred to as a substitutional alloy.
Brass was discovered around 500 BC. Although it is primarily made up of zinc and copper, it may contain other elements, as is sometimes the case with bronze. There are several similarities between brass and bronze, with brass being recognized by its large percentage of zinc and the absence of tin, although in the case of tinned brass alloys this may at times be even more difficult to distinguish.
Lead is commonly added to brass to increase its machinability, along with other unique elements that are built into the different brass alloys.
Some properties of brass:
- Density: About 8.73 g/cm3
- Melting point: Relatively low at 900°C - 1000°C (1,652°F - 1,832°F), depending on the alloy
- Color: May appear as a bright gold, copper or sometimes even silver color, depending on the ratio of zinc to copper added
- Friction coefficient: Similar to bronze, it exhibits low friction when in contact with other metals
- Heat conduction: A good conductor of heat
- Corrosion-resistant, especially in the case of galvanic seawater corrosion
Corrosionpedia explains Brass
Malleability and Types of Brass
The zinc content in brass is what determines it malleability. Those brasses that contain more than 45 percent zinc cannot be worked on, whether hot or cold. A type of brass known as white brass is usually of little industrial importance, but when in granulated form is used in brazing (soldering). White brasses also form a basis for certain alloys that are used in die-casting.
Malleable brasses can be subdivided into those that can be cold worked, and those that possess greater zinc content, which need hot working. The former, which are called alpha brasses, are widely used to manufacture pins, bolts and ammunition cartridge cases. The latter, known as beta brasses, are not as ductile but make up for it by being stronger and thus suitable for manufacturing faucet handles, window and door fittings, and other fixtures.
Another group of brass includes those with other elements (besides copper and zinc) that are added to improve several physical and mechanical properties such as corrosion resistance, machinability and color. This third group of brasses contains lead brasses that are easily worked on, the naval and admiralty brasses that are made up of a small amount of tin to improve its resistance to corrosion by seawater, and the aluminum brasses that provide strength and corrosion resistance.
Use Applications for Brass
Brass casts well and is reasonably durable and attractive while possessing antimicrobial qualities due to its high copper content. The most common uses for brass are for manufacturing musical instruments, decorative trims, fasteners, bullet casings, and many more items.
Brass is frequently and easily recycled, thus many parts are made from recycled brass.