Copper, brass, and bronze are three different metals used for a wide variety of parts and applications. These three have a lot of similarities, so it can be difficult to tell the difference, and understand which one is better for your project.
To start, brass and bronze are alloys that include copper. So it makes sense why you might think the metals are essentially the same thing. Copper is an element, but pure copper isn’t typically used to make copper parts.
That means, in most cases, copper, brass, and bronze parts are all slightly different mixtures of pure copper and a few other metals like tin, lead, and zinc.
Keep reading to better understand the differences between the three materials and choose what’s best for your parts and components.
You probably know that pure metals are rarely used for anything. Different elements are mixed together to form a metal alloy. This is done with high precision to enhance certain properties of the metal parts.
For example, a tiny amount of lead can be added to a copper alloy to improve the machinability of the metal. The differences between copper, brass, and bronze are because of the different elements added to the alloys.
As mentioned, copper is a pure metal. Pure copper (99.95% copper) is used for wiring, or applications where conductivity is a high priority. Even a slight drop in the purity can have a significant impact on the electrical conductivity.
Pure copper is a softer, malleable metal, so it’s great for wiring and sheet metal, but not as good for parts that need more durability. Copper alloys usually have a small amount of beryllium, tellurium, or lead to improve machinability and durability.
Copper can be used in a CNC mill, CNC turning machine, or a Swiss screw machine to manufacture parts. Because it’s a softer metal, it has a lower machining cost.
Raw Material Cost: High
Machining Cost: Medium
Brass is one of the easiest metals to machine. Machined brass parts have many advantages. Brass is durable, cost-efficient, and creates a tight seal for fittings. Brass parts also have great heat and corrosion resistance.
Brass alloys are a mixture of about 65% copper and 35% zinc. Other trace elements like lead, zinc, and iron are added to improve certain characteristics.
Because of the added zinc, brass parts are significantly stronger than copper. Brass is also less expensive compared to copper. Brass parts don’t have the same conductivity as copper, so they’re less common in electronics, or systems where conducting heat is needed.
Brass parts are commonly used in applications in the engineering, plumbing, and steam industries because brass fittings offer a low friction coefficient and high corrosion resistance. Because brass is a harder metal, it’s more subject to cracking compared to copper.
Bronze is a copper-based alloy that consists of varying amounts of copper and tin. Trace amounts of other metals, like aluminum, manganese, phosphorus, and silicon, are also found in bronze alloys.
The primary difference is the strength of the alloy. Bronze is stronger and more durable than copper and brass. Bronze can withstand more weight, and has a higher yield and tensile strength. Higher strength means that bronze parts are used in applications where parts are more subject to denting or wearing down.
Like copper and brass, bronze is also a “no-spark” metal. And because it’s stronger, bronze is used for hammers, mallets, and wrenches that won’t spark when they’re struck against another metal.
The easiest way to spot the difference between copper, brass, and bronze parts is the color. Most copper alloys have a reddish-brown color. Brass has a brighter yellow-gold appearance. And bronze is usually a duller gold or sepia color.
But, depending on the alloy and secondary operations, the metals can look very similar.
Choosing the right metal for your part is critical. And with three different options that can look very similar, you need to know what to pay attention to.
Here’s what you should keep in mind when deciding between these materials.
Copper has the highest flexibility and conductivity. That makes it better for parts that need to flex under pressure without cracking. And copper is best for parts that need to conduct heat or electricity.
Brass is often considered the most suitable for general applications. It’s malleable, easy to cast, relatively inexpensive, and low-friction.
Bronze is the hardest metal alloy, and best suited for saltwater and sea environments. Parts used in marine environments need to have high corrosion resistance. Higher durability and hardness also make it better for high stress marine applications.
Spex is an ISO 9001:2015 certified precision machine shop in Rochester, NY. We machine thousands of unique metal and polycarbonate parts every month for different industries around the world. Reach out to our team to see if we can help with your next project.
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