Brass Material has played a significant role in the development of human civilisation. Its history dates back to ancient Mesopotamia in the second millennium BC, when metalworkers used it to make coins, ornaments and copper-zinc alloys.
Today, modern industry relies on brass for its decorative and functional properties. Brass metal is widely used and available in various grades with different characteristics. Its machinability, beauty, strength and corrosion resistance make it popular in a wide range of industries. It is therefore important to understand the different types of brass material to determine the right one for your project. Let us give you a detailed introduction to brass metal to help you get the job done.
The advantages, disadvantages, applications and comparisons of brass that we provide here will also help you make the best choice.
Brass is a metal alloy consisting of copper and zinc, together with elements such as iron and lead. In general, brass is 66% copper and 34% zinc. Brass alloys with a higher copper content tend to be softer and look more like gold. Brass alloys with a lower copper and higher zinc content are harder and look more like silver.
However, you can vary the ratio of copper to zinc in brass to create different shades and mechanical, chemical and electrical properties.
There are many different grades and types of brass because the proportions of copper and zinc elements are varied to achieve the specific properties of the brass material. The addition of other alloying elements such as aluminium, tin and manganese also helps to change the properties of this metal. The following are the most common types of brass:
Alpha Brass is a single phase alloy with a composition of 35-45% zinc and 55-65% copper. Its crystal structure is face centred cubic or FCC. The ductility of alpha brasses gives them excellent cold working properties. They are widely used for forming and drawing and have good corrosion resistance. The addition of small amounts of iron, aluminium and silicon can improve the mechanical properties of these alloys and harden them by cold working.
Alpha Brass has many advantages, most notably its excellent corrosion resistance, good cold working properties and attractive appearance. It is often used for architectural and decorative purposes because of its bright colour and ability to retain a polished lustre.
High zinc beta brasses are approximately 15% copper and 85% zinc. They have a single phase structure and a BCC crystal structure. These brasses are mainly used for die casting due to their high fluidity and low melting point. They can be strengthened by heat treatment and have good wear resistance.
However, they are more susceptible to stress corrosion cracking than other types of brass. High zinc beta brasses are popular because they are less expensive than other forms of brass and have excellent castability and wear resistance. They are often used to make die castings, including fasteners, hinges and locks.
Alpha-beta or duplex brasses contain approximately 55-60% copper and 35-45% zinc. They are composed of alpha and beta phases. Duplex brasses have higher strength, hardness and low cold ductility compared to alpha brasses.
However, alpha-beta brasses are less expensive than alpha brasses due to their higher zinc content. The higher zinc content in these brasses makes them suitable for hot working. Alpha-beta brasses are brighter than alpha brasses and have the highest strength at 45% zinc content. Typical applications for these brasses include architectural profiles, radiator valves, hinges, gas appliances, taps and pipe fittings.
Other common brass materials include:
Alloy 260 (Cartridge Brass)
Alloy 260 is also known as cartridge brass. It consists of exactly 70% copper and 30% zinc. This brass has good formability and can be cold worked. Engineers often use Alloy 260 to make automotive parts, ammunition and fasteners.
This brass alloy consists mainly of about 60% copper and 40% zinc. It also contains significant traces of iron. Manufacturers often use 280 alloy as an economical alternative to copper hull plating to prevent marine growth such as barnacles from forming on the hull.
Free-machining brass is composed of approximately 60% copper, 35.5% zinc, 3.7% lead, and trace amounts of iron. Alloy 360 is one of the most easily machined brass grades. It is a high-quality brass metal for brazing and welding applications. Typical applications for this brass include valves, fittings, fasteners, and hardware components.
Alloy 385 or architectural bronze consists of 59% copper, 42% zinc and precisely 3.5% lead. Its constituent elements significantly increase its machinability and formability. In addition, this alloy is easily formable, making it an ideal architectural material for aluminum profiles.
Alloy 464 is composed of approximately 59% copper, 40% zinc, 1% tin and a small amount of lead. Marine brass is highly corrosion resistant and can withstand a wide range of temperature changes. In addition, this brass alloy is suitable for a variety of processes such as cold and hot forming, welding, bending and brazing. Product designers and mechanics often use 464 alloy for various fittings on the deck of a ship.
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