Brass and bronze are often considered one and the same, since they’re part of the world of copper alloys. For engineers, it’s a different story. The slight differences between the two can make enormous impacts on the functionality of the parts, their manufacturability, and the overall cost. Making a part out of bronze instead of brass can cost multiple times more money, take us much longer, and can corrode and fail relatively quickly; that’s why this decision is so important.
Our experts at Rapid Axis put together this guide to give you a run-down of the differences between brass and bronze, and which option is right for your project.
What Is Brass?
Brass is a copper-zinc alloy that’s used for machined components, fittings, and high-precision hardware. Brass is usually about 55% to 70% copper, and zinc makes up the balance. Some brass includes aluminum, tin, or lead to make the material more machinable or stronger.
A common brass grade that we use on our CNC machines is C360. It’s a great choice for high-volume precision parts like fasteners and electrical connectors.
C260 has good formability and strength, while C464 brass is great for maritime applications since it has great corrosion resistance.
Brass is a really common choice for plumbing fittings and valve bodies since it can be quickly mass-produced while providing high corrosion-resistance and durability.
Pros of Brass
One great benefit of brass is that it can be machined, allowing us to create custom parts for your operation. Brass is also typically more affordable than bronze, so you can stay within your budget.
In the machine shop, brass doesn’t wear out tooling excessively, so machine shops can charge less for each project. In addition, it’s easy enough to machine a piece of brass, so we can achieve better dimensional accuracy.
As mentioned, brass is also extremely corrosion-resistant, so it can be used in plumbing and fluid handling systems.
People don’t realize it, but brass is also antimicrobial, so it can be used in medical and consumer applications.
Cons of Brass
Even though we can machine brass, it has a much lower strength as compared to bronze alloys. If you’re looking for a material that can take a beating and handle heavy loading, you’ll have to look elsewhere. Brass parts are quick to deform, wear out, and get marred.
Also, the wrong alloy of brass can break down and experience dezincification in chloride-heavy environments, so make sure you triple-check the brass alloy you’re using.
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What Is Bronze?
Bronze is another copper alloy, but this one is primarily mixed with tin. Bronze can also include aluminum, silicon, manganese, and phosphorus as added elements to fine-tune the mechanical properties.
While brass relies heavily on zinc, bronze very rarely contains zinc.
You might recognize bronze from historical weapons and tools, and it’s still used to this day in high-wear and load-bearing applications. Bronze offers great strength and durability.
- C932 bronze is used in sleeve bearings due to its excellent friction coefficient.
- C954 bronze has higher strength and corrosion resistance, so people use it in marine environments.
Pros of Bronze
Bronze is a great choice for high-load, high-friction applications. It has great strength and durability that will stand up to cyclic loading over a longer period of time.
Bronze alloys are also corrosion-resistant, making them a good choice for marine and chemical applications.
In general, bronze is a great option for long-term performance when it comes to sliding or moving parts.
Cons of Bronze
The big drawback is that bronze is very difficult to machine. The cutting forces are higher and it’s hard to control the chips, so we need to closely monitor our CNC settings before starting a bronze project.
Bronze also tends to be more expensive than brass, and the cost difference grows even more if you try machining a piece of bronze. We typically have to use carbide-tipped tooling, which is more expensive specialized tooling, so make sure you pick a machine shop that has direct experience with bronze.
Brass vs Bronze
While they might look similar, brass and bronze offer very different characteristics.
Brass is less expensive, not as strong, and easier to machine. It’s a good choice for mass-produced parts, fittings, and plumbing parts.
Bronze is much stronger but more expensive and more difficult to machine. You might use bronze for heavy-duty, wear-resistant parts like bearings and bushings.
Conclusion
These two copper alloys are very popular options, and they’re used for very different applications. The right material choice will determine how well your part operates, how expensive the part is to make, and the overall lead time. If you’re still not sure, reach out to our experts at Rapid Axis. We have experience working with both brass and bronze (plus dozens of other materials), so we’ll help you pick the perfect material for your project.
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FAQs
The main difference between brass and bronze lies in the added elements and amount used. Brass is mostly a combination of copper and zinc, while bronze is mostly a combination of copper and tin.
No, bronze is much stronger than brass. Brass is easier to machine and offers better corrosion resistance, but it is not nearly as strong as bronze.
Brass is significantly easier to machine than bronze, especially a free-machining grade like C360.
The best brass grade for CNC machining is C360 free-machining brass. Our machinists use it more often than other brass grades since it has excellent chip control and offers a nice surface finish capability.
Called “bearing bronze”, C932 bronze is really common for high-wear applications like bushings and bearings. Aluminum bronze C954 is another great option since it offers high strength and durability.
