When you think of brass, the first thing you would probably imagine is a musical instrument, particularly a trumpet or a saxophone. While many musical instruments are indeed made of brass, they are not the only items made of such material. There are countless others, some of which are everyday objects, such as doorknobs, drawer pulls, and handrails.
Brass is quite a common metal but very few people are truly familiar with it, and it’s not difficult to understand why. Apart from having a plain appearance, brass also comes in numerous varieties. Furthermore, the color of brass can be engineered to suit a wide range of design applications, which is why it is almost always mistaken for other shiny metals.
What is brass made of?
Brass is the resulting alloy when you combine about 67% copper and 33% zinc. This standard composition can be altered to produce different types of brass. Minute amounts of other metals, such as lead, phosphorus, aluminum, manganese, and silicon can be added to the mixture to further improve the properties of brass. For instance, adding up to 2% lead could give brass better machinability.
Not all combinations, however, produce useful versions of brass. Some make brittle and soft kinds, while others too difficult to cold work. Another problem that may arise is dezincification, which is characterized by the gradual increase in porosity of brass due to an excessive amount of zinc.
Useful Properties of Brass
If you are familiar with copper and zinc, it will be easy for you to understand the nature of brass. We know that copper is extremely durable, able to last for thousands of years due to its ability to form patina, a green layer of material that protects its surface from weathering. Zinc, on the other hand, is known for its high corrosion resistance and density, which makes it incredibly impermeable. Now, let’s take a look at brass and its useful properties.
– Like copper, brass is also resistant to corrosion. It’s no wonder manufacturers prefer brass channel and tube products to other metal supplies. With the right composition, brass can even hold out in seawater, which is ten times harsher than tap water. Unfortunately, brass tarnishes quickly, which is why brass furniture and accessories must be regularly polished to stay shiny.
– Standard versions of brass are prized for their malleability. Meaning, they can be molded into different shapes and thicknesses without applying heat. Compared with bronze, brass is easier to cold work, weld, and braze. Adding a little bit more zinc helps improve this metal’s machinability.
– Like copper, brass also has a considerable heat and electrical conductivity, around 40% that of copper. It doesn’t quickly burn under high voltage like silver and other conductive metals. This is why brass is the preferred material for machine parts that function as conductors.
– Brass is also anti-bacterial, a property that is characteristic of most non-ferrous metals. Their molecules produce ions that target a certain protein in single-celled microorganisms, resulting in their demise. The entire process takes about two to four hours depending on the type of metal involved. This is the reason why copper alloys, such as brass, are ideal for filtration systems.
– There’s no denying the majestic appearance of standard brass. Its glittery yellow tone rivals that of authentic gold. Those who are looking for a cheaper alternative to gold in their crafts must consider brass.
Major Classifications of Brass
There are currently over 60 types of brasses available commercially. They are classified according to the ratio of their copper and zinc content. As mentioned, by changing the ratio of what brass is made of, you can produce brasses of varying properties. To better identify each brass type and measure their performance, they are methodically classified into three forms.
– More commonly known as soft brasses, these are brasses with 65% copper and 35% zinc. This much copper is what makes these brasses malleable and easy to work cold. They also look more gold-like than the other forms of brasses.
– Brasses with 55-65% copper and 35-45% zinc are classified as semi-hard or alpha-beta brasses. They are slightly harder than alpha brasses, which is why they are usually worked hot. This slight change in composition gives these brasses a brighter, less golden hue. Additionally, alpha-beta brasses are also less resistant to corrosion than alpha brasses.
– The hardest types of brasses belong to the beta group. Theses brasses have 50-55% copper and 45-50% zinc. Due to their hardness, they are quite impossible to work unless they are heated. The high amount of zinc also poses the risk of dezincification.
When purchasing brass for your projects, always be precise about the composition to make sure you’ll get the exact quality you need. The last thing you want is to use soft brass for structural applications. You must always consult with a metal expert before choosing a specific grade of brass. You may also get your supplies from top brass suppliers like Rotax Metals, especially because they supply North America with superior copper products.