Selecting the right material is key to a successful project, from manufacturing to a product’s life cycle. Bronze and brass are both copper-based alloys. They have a millennium of history and remain essential materials in today’s society. Whether the intended application is marine, electrical connectors, or decorative elements, understanding the differences is crucial. Prototek works with both of these materials in our CNC machine shops and fabrication facilities. If you have further questions, don’t hesitate to reach out to our team!
In this blog post, we will cover the properties, pros, cons, and cost of these copper alloys.
What are brass and bronze alloys
What is brass?
It is an alloy with two main components, copper and zinc. They can also have small amounts of other elements such as lead, aluminum, or silicon to enhance the alloy’s properties. With a bright, gold-like appearance, it is suitable for decorative applications such as hardware and home interior design elements. It is also corrosion-resistant, durable, and easy to machine, which makes it popular for plumbing and marine applications.
What is the base composition of brass?
Copper and zinc are the two main elements in brass. Specific grades may include lead, tin, aluminum, or silicon.
What are the main grades of brass?
- Cartridge Brass (C26000):
- 70% Copper
- 30% Zinc
- Free-Cutting Brass (C36000):
- 61.5% Copper
- 35.5% Zinc
- 3% Lead
- Navel Brass:
- 59% Copper
- 40% Zinc
- 1% Tin
- Architectural Bronze (C38500):
- 57-59% Copper
- 39-41% Zinc
- 2-3% Lead
Note: Architectural bronze is not a true bronze. It is a high-lead brass alloy.
What is bronze?
It is an alloy with two main components, copper and tin. They can also have small amounts of other elements such as aluminum, nickel, or zinc to enhance the alloy’s properties. With a reddish-brown coloring, it is common for industrial and artistic applications—for example, statues. It is also corrosion-resistant and holds up well in salt water, making it excellent for marine applications as well as a good choice for bearings and gears.
What is the base composition of bronze?
Bronze is primarily made up of Copper and Tin. Certain alloys may include aluminum, silicon, phosphorus, or manganese for different properties..
What are the main grades of Bronze?
- Phosphor Bronze:
- 85-95% Copper
- 4-10% Tin
- 0.01-0.35% Phosphorus
- Potentially a minuscule amount of lead.
- Aluminum Bronze:
- 75-90% Copper
- 4-14% Aluminum
- 1-5% Iron (Frequently)
- 5-6% Nickel (Often)
- Minuscule amounts of manganese, silicon, or zinc.
- Manganese Bronze:
- 55-68% Copper
- 22-42% Zinc
- 2.5-5.0% Manganese
- Often with minuscule amounts of iron and aluminum.
Material Properties: Brass vs Bronze
| Property | Phosphor Bronze | Brass C36000 |
|---|---|---|
|
Tensile Strength (MPa) |
324-965 |
338-469 |
|
Yield Strength (MPa) |
131-552 |
124-310 |
|
Hardness (Brinell) |
50-90 |
~100-130 |
|
Elongation (%) |
60-70 |
10-50 |
|
Fatigue Resistance |
Good-High |
Moderate-Good |
|
Density (g/cm3) |
8.9 |
8.5 |
|
Melting Point (C°) |
954 |
885 |
|
Thermal Conductivity (W/m•K) |
84 |
115 |
|
Electrical Conductivity (% IACS) |
11-20 |
26 |
|
Corrosion Resistant |
Excellent – patina and oxide films. |
Good – dezincification risk. |
- Brass: Easy to machine, thermally/electrically conductive, and easy to form.
- Bronze: Higher strength, hardness, wear resistance, and corrosion resistance due to protective oxide films.
Comparing Brass vs Bronze in Specific Environments
| Environment/Property | Brass | Bronze |
|---|---|---|
|
Marine/Seawater |
Can have dezincification unless a specialty alloy. |
Excellent corrosion resistance. (tin, silicon, and aluminum alloys) |
|
High-Temperature |
Lower strength with temperature elevations. |
Maintains properties at hirer temperatures. (silicon bronze) |
|
High-Pressure/Load |
Light-duty bushings and gears. |
Bearings, bushings, and gears under heavy load. |
|
Electrical/Electronic |
Most electrical connectors. (conductivity and machinability) |
Connectors where corrosion resistance is critical. |
Decision-Making Considerations
Cost
- Brass: Roughly $2.00-$2.70 per pound, it is stable and available.
- Bronze: Higher, can vary significantly by grade and the alloying elements.
Machinability
- Brass: C36000 is the industry standard, and extremely machinable.
- Bronze: 20-60% varies by grade, but has more tool wear and slower machining rates.
Weldability
- Brass: C36000 is good for soldering, fair for brazing, and poor for most welding.
- Bronze: Generally good for arc welding.
Castability
- Brass: Excellent.
- Bronze: Excellent.
Formability
- Brass: Good. Depending on the grade.
- Bronze: Moderate. Some grades are less ductile.
Recyclability
- Brass: Highly recyclable and valuable in the scrap market.
- Bronze: Highly recyclable.
Questions to ask yourself when deciding which one is the most suitable for your project.
- Is cost the main factor? Choose brass.
- Is machinability a requirement? Choose brass.
- Is the part going to be exposed to high wear or marine and corrosive environments? Choose bronze.
- Is electrical conductivity necessary for your project to be successful? Choose brass.
- Is complex forming or bending a requirement? Choose brass.
| Requirement | Brass | Bronze |
|---|---|---|
|
Cost Sensitivity |
Cost is primary concern. |
Willing to pay more for performance. |
|
Machinability |
High-speed, precision machining needed. |
Machining is secondary to wear and corrosion resistance. |
|
Corrosion Resistance |
Moderate required for non-marine environments. |
High, especially in marine and chemical environments. |
|
Wear Resistance |
Moderate |
High – bearings, bushings, and springs. |
|
Electrical Conductivity |
Important, for example terminals. |
Less critical. |
|
Formability |
Complex shapes with bends. |
Less forming, more casting or wear parts. |
|
Weldability |
Soldering and brazing preferred. |
Arc welding required |
Key Takeaways for Brass vs Bronze
- Brass: Excels in machineability, cost-sensitive, electrical, and decorative applications.
- Bronze: Excels as a go-to material for high wear and tear situations, corrosive, and heavy-load applications, such as marine hardware and bearings.
- Know the Grades: Once you’ve decided whether brass or bronze is suitable for your project, assess the different grades.
- Brass and Bronze: Are sustainable and easy to source. The main differences come down to performance, and those differences are significant.
FAQs
What is brass vs bronze?
Brass is an alloy of copper and zinc. Bronze is an alloy of copper and tin. Brass is known for its formability and corrosion resistance. Bronze, on the other hand, is valued for its strength and durability.
Define: Brass
Brass typically contains 55-95% copper and 5-45% zinc. It is known for having a golden color, corrosion resistance, and good machinability. Brass is common in a variety of applications, such as plumbing fittings, musical instruments, and decorative items.
Define: Bronze
Bronze is an alloy composed of copper and tin, known for its durability, corrosion resistance, and attractive appearance. It has been used for centuries in various applications, including sculptures, coins, and industrial components.
What does brass look like?
Brass is a yellowish-gold metal that has a warm, lustrous appearance—often described as having a rich, antique look, with a slightly reddish tint. The surface of brass can be polished to a high shine or left with a more muted, brushed finish.
What does bronze look like?
Bronze is a warm, rich metal with a distinctive reddish-brown hue. It has a smooth, lustrous surface that can range from a deep, dark patina to a bright, polished finish. The color and texture of bronze may vary depending on the specific alloy and finishing process used.
