Copper, brass, and bronze, generally classified as non-ferrous metals, belong to the same group called Red Metals. They all own features of corrosion resistance, high electric/thermal conductivity, and weldability that make them widely used across industries like architecture, electronic, artwork, and machine.
While these metals share similar characteristics, each possesses unique properties which are crucial for specific applications. Understanding their differences is important for selecting the most suitable one for your projects.
This article shows the distinct properties of each, clarifying the differences between copper, brass and bronze. We’ll guide you to find a better solution on choosing the right material for your project.
An Overview of Copper
Copper, labeled as Cu on the periodic table, is a naturally occurring metallic element with a distinctive reddish-orange color. It is one of the few metals found in nature that can be directly processed，and because copper is purer it often has more value and is able to be recycled without losing any quality.
Properties of Copper
Excellent electrical and thermal conductivity
Ductility
Corrosion resistance
Antimicrobial
Grades of Copper
Copper is classified into various grades based on its purity, as well as the type and content of other added elements. Here are some of the common grades of copper:
Electrolytic Tough Pitch (ETP) Copper（C11000）: Containing a minimum of 99.90% copper, is the most common grade of copper. It exhibits not only the highest level of thermal and electrical conductivity, but also excellent formability and ductility.
Oxygen-Free High Conductivity (OFHC) Copper (C10100): A high-conductivity copper with extremely low levels of oxygen. This characteristic enhances its electrical conductivity and reduces the risk of oxidation.
Deoxidized High Phosphorus (DHP) Copper (C12200): is mechanically similar to C11000 but includes a small amount of phosphorus. This addition removes oxygen from the metal, enhancing its weldability and brazing capabilities while also preventing hydrogen embrittlement.
Tellurium Copper (C14500)：Contains a small percentage of tellurium, usually between 0.4% and 0.7%. The addition of tellurium enhances machinability without significantly affecting conductivity.
Applications
Electrical wiring and electronics
Plumbing and pipework
Heat exchangers and HVAC systems
Medical applications such as surgical instruments, dental tools, and implants
An Overview of Brass
Brass is an alloy primarily composed of copper and zinc, along with trace amounts of other metals. The proportions of zinc and these additional elements significantly affect both the color—ranging from a deeper reddish copper to a lighter yellow gold—and the mechanical properties of brass. For example, increased zinc content generally enhances strength but may reduce ductility, making the alloy harder and more brittle. Additionally, brass is typically less expensive than pure copper due to the inclusion of zinc, which costs less.
Properties of Brass
Good mechanical properties
Excellent formability（lower melting point than copper，approximately 900°C）
Good electrical and thermal conductivity
Relatively good corrosion resistance
Grades of Brass
There are various grades of brass, primarily classified based on the proportion of copper to zinc and the addition of other alloying elements. The common ones are as follows:
Cartridge Brass (C26000): Typically made up of 70% copper and 30% zinc, this alloy excels in cold working, offering good strength and ductility. It's perfect for ammunition casings, radiator cores, heat exchangers, and electrical components like connectors and terminals.
Yellow Brass (C27200): With a higher zinc content than C26000, it has a bright yellow color and good formability. It’s often used in industrial and architectural applications.
Low-Leaded Brass (C33000): Highly machinable with a low percentage of lead, this alloy complies with stricter environmental standards, making it ideal for fittings like in drinking water systems.
Clock Brass (C35300):Its excellent machinability allows for precision machining , especially in clock and watch manufacturing.
Free-Cutting Brass (C36000):Known for outstanding malleability and machinability, it‘s widely used for soldering, brazing, and making fittings, fasteners, and valves. It’s the most common type of brass.
Architectural Bronze(C38500):Chosen for its excellent machinability and attractive appearance, it’s ideal for architectural hardware and decorative elements.
Naval Brass (C46400): With a small amount of tin, offers superior resistance to seawater corrosion, making it perfect for marine applications and components exposed to harsh environments.
Applications
Decorative applications (similar appearance to gold and available in a variety of shades, applicable in jewelry, door trims, etc.)
Musical instruments
Plumbing fittings
Electronics and electrical terminals
An Overview of Bronze
Bronze, a golden-brown alloy primarily composed of copper and tin, includes elements like aluminum, manganese, silicon, and phosphorus in small amounts. It has been used for thousands of years, dating back to ancient civilizations of 3500 BC.
Properties of Bronze
High strength and hardness
Superior corrosion resistance
Excellent thermal conductivity and good electrical conductivity
Low metal-to-metal friction
Greater brittleness
Grades of Bronze
As metal processing technology advances and the demand for improved material properties increases, researchers have explored adding other elements to enhance the performance of bronze. Below are the common varieties of bronze.
High-Leaded Tin Bronze（C93200): Commonly used for bearings (often referred to as "Bearing Bronze"), bushings, pump and valve components, and mechanical applications where moderate strength and good resistance to wear and tear are needed.
Aluminum Bronze（C95400): Known as the hardest and strongest type of bronze, it is highly resistant to corrosion in saltwater, making it suitable for pumps, valves, and ship components. It is also used in heavy-duty applications such as aircraft landing gear.
Phosphor Bronze (C51000): Known for its excellent fatigue resistance, good corrosion resistance, and high strength, Phosphor Bronze is commonly used in applications such as springs, fasteners, electrical connectors, and bearings, where components are subjected to repetitive stress and harsh environments.
Silicon Bronze(C65500):Possesses high strength, excellent corrosion resistance, especially in marine conditions, and good machinability. It is widely used for marine hardware, architectural applications, and pump and valve components, where longevity and aesthetic appeal are critical.
Applications
Bearings and bushings（The most common application of bronze）
Marine applications such as marine hardware, propellers, and ship components
Statues and sculptures
Electrical connectors and springs
Differences Between Copper, Brass and Bronze
To differentiate their distinct properties , let's start by examining the table as below to make a preliminary comparison.
Property
Bronze
Brass
Copper
Element composition
Copper, tin, others
Copper,zinc, others
Pure copper
Color/Appearance
Reddish-brown
Gold-like
Orange-red
Corrosion resistance
Excellent
Intermediate
Very good
Electrical conductivity
Moderate
High
Very High
Thermal conductivity
229~1440 BTU/hr-ft²-ºf
64 BTU/hr-ft²-ºf.
223 BTU/hr-ft²-ºf
Melting point
Approx. 950 - 1050°C
Approx. 900-940°C
1085°C
Density
7.5~8.8g/c㎥
8.4~8.7g/c㎥
8.96g/c㎥
Hardness
40~420 BHN
55~73 BHN
35 BHN
Yield strength
125-800 MPa
95 to 124 MPa
33.3MPa
Tensile strength
350 to 635 MPa
338 to 469 MPa
210MPa
Machinability
Fair to Good
Good to Excellent
Fair
Weldability
Poor
Good
Excellent
Next, let's make specific comparisons in element composition, appearance, corrosion resistance, conductivity, density&weight, hardness, strength, machinability and weldability.
Element Composition
Copper is a pure elemental metal, with the chemical symbol Cu and atomic number 29 on the periodic table.
Brass, a copper-zinc alloy, contains copper (60%~90%) and zinc (10%~40%), occasionally alloyed with tin, lead, aluminum, or nickel.
Bronze consists mainly of copper (80%~90%) and tin (10%~20%), with occasional additions of other elements like aluminum or zinc.
Appearance
Brass, as its name suggests, has a gold-like appearance. This makes it easy to differentiate from the other two. Bronze and copper share similar reddish-brown color. In comparison, copper has a distinctive reddish-orange color compared to the dull gold color of bronze. Additionally, bronze often exhibits faint rings on its surface, which can be as an important differentiating feature.
Corrosion Resistance
Bronze typically shows better corrosion resistance than copper and brass, particularly in salt water environments due to its tin content. Moreover, its resistance can be enhanced by incorporating additional elements such as aluminum and phosphorus.
Copper, though slightly less resistant in marine environments, forms a protective layer of patina over time, which helps prevent further deterioration.
Brass,while still offering some resistance, is generally less resistant and may experience accelerated corrosion when exposed to specific chemicals or saltwater conditions.
Conductivity (Electrical and Thermal)
Copper, brass, and bronze all demonstrate varying levels of electrical and thermal conductivity due to their distinct compositions.
Electrically, copper stands out as one of the most renowned metals for its outstanding electrical conductivity, boasting a 100% conductivity rating. Brass exhibits about 28% of the conductivity of copper, while bronze lags behind at around 15%.
Thermally, bronze boasts the highest thermal conductivity among the three, with copper securing second place, and brass trailing behind with the lowest thermal conductivity.
Density & Weight
Copper, a pure element, with a relatively high density of 8.96g/cm³, exhibits the highest weight among the three metals. Brass is an alloy of copper and zinc, with its density decreasing as the proportion of zinc increases. This is because zinc has a lower density compared to copper (7.14 g/cm³). Bronze is primarily an alloy of copper and tin, with its density varying depending on the amount of tin or other additional elements used (such as aluminum, silicon, or phosphorus). The density of tin is approximately 7.31 g/cm³, which is lower than that of copper.
Hardness
According to values on the Brignell hardness scale, Bronze> Brass > Copper.
Pure copper is the softest among the three metals, while bronze is the hardest but susceptible to cracking because it is more brittle.
Strength (Yield and Tensile Strength)
Strength refers to the ability of a material to resist deformation and damage when subjected to external forces. There is a strong correlation between hardness and strength (both yield and tensile). Harder materials are usually stronger but may be less ductile. Therefore, in terms of strength, Bronze> Brass > Copper.
Machinability
Copper is a bit challenging to machine due to its softness. Generally, there demands right tools and techniques for effective machining. During machining, it tends to produce long, stringy chips, which can sometimes cause problems if not properly managed.
Bronze exhibits good machinability. Its moderate hardness and strength reduce the risk of deformation, enabling it to withstand cutting and other machining operations. Furthermore, most bronze alloys demonstrate relatively low wear rates, contributing to the durability of machining tools. However, some bronze alloys like high-silicon bronze or other special bronze alloys may contain abrasive particles that can accelerate tool wear during machining.
Brass is highly machinable compared to copper and bronze. It produces shorter, more manageable chips, making it easier to machine. Additionally, brass contains lead sometimes, enhancing machinability.
Weldability
All three metals are weldable. Copper is generally considered good for welding, but its high thermal conductivity requires higher energy inputs for optimal welds. However, Oxygen-free copper and deoxidized copper excel in weldability due to their reduced susceptibility to oxidation during welding, making them highly favored for various applications.
Brass contains zinc, which has a lower boiling point than copper. During welding, zinc vaporization can lead to weld porosity and the release of hazardous zinc oxide fumes. Techniques such as MIG, TIG, and especially brazing are commonly employed to mitigate these challenges.
Bronze may experience brittleness in the heat-affected zone and porosity. TIG welding is often used for bronze to reduce these issues.
How to Select the Right Metal for Your Projects
When choosing the right material for a project, it is important to consider all the properties of each metal and how they will affect your project. Some of the key points to keep in mind will help you select better materials.
General Usage
Bronze is the best choice for marine applications because of its excellent resistance to seawater corrosion.
Brass is widely used in daily life such as doorknobs and musical instruments due to its gold-like appearance.
Copper's superior conductivity makes it indispensable in electrical wiring and heat exchangers. Moreover, copper is often used to make food flasks and food heaters due to its antimicrobial properties.
Degree of Versatility
Although copper, brass and bronze are all durable metals, they have different degrees of versatility.
Copper stands out with its exceptional ductility, offering excellent flexibility for manufacturing processes involving metal forming and bending.
Brass exhibits excellent machinability and decent malleability, making it suitable for both decorative and functional components that require intricate machining.
Bronze, while possessing good machinability, lacks the ductility of copper and brass, making it less adaptable for applications requiring deformation but ideal for wear-resistant parts and components exposed to corrosive environments.
Cost
The cost of copper, brass, and bronze is mainly decided by the compositions and processing requirements. Copper is the most expensive among the three metals regarding their compositions and elements’ proportion. Although all of three contain copper, the percentage is far lower in brass and bronze than in pure copper as alloying elements are mixed in. This reduces the cost of brass and bronze.
The cost of copper, brass, and bronze is mainly decided by the compositions and processing requirements. Copper is the most expensive among the three metals regarding their compositions and elements’ proportion. Although all of three contain copper, the percentage is far lower in brass and bronze than in pure copper as alloying elements are mixed in. This reduces the cost of brass and bronze.
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