Brass is one of the oldest metal alloys in existence. An alloy of copper and zinc, this metal is prized for its many valuable properties, which suited a great deal of applications even in prehistory. Development of brass, however, only took place until the post medieval period because it’s only during then when metallurgists realized that the zinc vapor that makes the production of brass possible is actually a different kind of metal and not just a gas.
During the time when brass had no exact classification yet, it is often used to refer to any type of bronze given that copper is also its base metal. It soon became clear that brass is an entirely different metal from bronze due to its distinct qualities. It has bright and lustrous yellow color that makes it look like gold, something you won’t see in bronze. It’s also harder yet more malleable than bronze.
Classifications of Brass
Like other alloys of copper, brass may come in a range of versions since its content can be manipulated. Each version exhibits a different set of properties, which is also why the benefits of using brass may vary. To avoid confusion and ease manufacturing, metallurgists came up with the brilliant idea to classify brass. They were grouped according to the amount of zinc or copper they contain. Those with higher copper content have better quality and are more expensive.
These are brasses that contain less than 37 percent zinc. Because zinc in these versions of brass only comes in small quantities, it easily dissolves into copper, which results in a uniform distribution of zinc atoms across the sea of copper molecules. The result is often a high-quality brass that is easy to cold work, weld, roll, draw, bend or braze. With more copper in its content, alpha brasses are the most corrosion resistant among the brass classes.
These brasses are a little bit tougher and less ductile or malleable than alpha brasses because they contain more zinc, specifically between 37 and 45 percent. That’s almost a 50-50 ratio with copper. One distinct characteristic of alpha-beta brasses is its almost dominant beta structure. Meaning, its grains look almost similar to pure brass. The quality, though, remains fine. To compensate for the valuable quality brass loses due to addition of more zinc, a miniscule amount of other metals, such as aluminum, silicon, or tin is added.
Brasses with more than 45 percent zinc are classified as beta brasses. These are the least popular types of brass. They are too hard to be cold worked so only hot working is applicable. Due to their high zinc content, beta brasses are susceptible to dezincification, a type of corrosion that leaches zinc from the brass, leaving a porous block of copper material.
Popular Types of Brass
After many years of exploring the properties of brass, over 20 different types of brass have been created, each of which has benefited an industry or two. Here are some of the most popular of them.
This alpha-beta brass has only 30 percent zinc, making it extremely resistant to corrosion. A miniscule amount of tin is added to increase its resistance to dezincification. Admiralty brass is the metal of choice for manufacturing tubes for coolers and evaporators as well as surface plates for desalination plants.
This type of brass has 77 percent copper, 20 percent zinc, and 2 percent aluminum. The presence of aluminum makes this brass extremely resistant to many kinds of corrosion. It’s no wonder aluminum brass is often used for applications that involve extreme heat and moisture, such as heat exchangers and condensers.
The name of this brass type was derived from its main purpose, which is for making ammunition cartridges. Cartridge brasses, together with common brasses, are the most popular types of brasses available. They contain about 70 percent copper and 30 percent zinc, the standard requirement for an alpha classification.
The “high” in the name of this brass type refers to the bass’s high tensile strength. Having 65 percent copper and 35 percent zinc, high brass has just enough softness and hardness to withstand powerful tensions. This is why this brass type is preferred for making bolts, screws, and rivets.
Of all the existing versions of brass, this is the softest, containing a staggering 95 percent copper and only 5 percent zinc. This makes the metal look almost like pure copper—reddish and supple.
Manufacturers in the electronic and industrial field are in constant hunt for metals that have high machinability. Luckily, they found that adding lead to brass makes the latter easy to cut with a satisfactory finish.
Like admiralty brass, naval brass possesses an extremely high corrosion resistance, allowing it to withstand even long exposures to saltwater, which is known to be ten times more corrosive than fresh water. This makes naval brass the perfect choice for most marine applications.
Advantages of Brass
The great variety of commercially available brasses is proof that they are highly in demand across many industries and that’s all thanks to their plethora of beneficial properties. Here are some of the brass benefits you should know before you use brass supplies for any of your projects:
Both copper and zinc are non-ferrous metals, and the other elements that are added to the alloy are mostly non-ferrous as well. It’s only natural that the resulting alloy when they are combined is also unsusceptible to corrosion via oxidation. Even though brass tarnishes easily, this only affects its luster and not its performance and durability.
The molecules of copper in brass are capable of producing ions that attack a certain type of protein in single-celled organisms, killing them instantly in the process. This makes brass and other copper-based metals for that matter an excellent material for water filtration and sanitation systems. They are even suitable for lavatories, kitchen sinks, and other areas in the house that provide breeding ground for harmful microbes.
Unlike pure copper and bronze, brass has a quite attractive appearance. Its natural color is very similar to that of gold, which is why it is often used as accessories and decorative element for buildings.
When looking for brass supplies, you need to know these important facts so that you can pick the right items and find the right supplier. It’s always advisable to find a metal supplier that specializes in copper-based products because they, more than any other store, know everything about brass, including all grades and manner of manufacturing. Reputable suppliers like Rotax Metals, which have many decades of experience, are your best option for a brass and copper sheet supplier.