Brass vs. Bronze vs. Copper: Machining Guide

As a common metal material, copper is widely used in machining due to its excellent electrical conductivity, thermal conductivity, and plasticity. copper plays an indispensable role in the automotive, aerospace, electronics, and other industries.There are subtle differences among brass, bronze, and copper and it’s difficult to detect with the naked eye. Therefore, designers are often confused about how to distinguish between the three when choosing materials. In fact, while these three have similar characteristics, they also have many different characteristics such as elemental composition.This article introduces the types, characteristics, and applications of commonly used copper materials for machining, and guides you on how to distinguish these three from a professional material perspective while providing copper material selection suggestions and typical technique flows.

Differences Between Brass, Bronze, and Copper

Alloy type

Brass Alloys

Here are some popular brass alloys included in rapid prototyping:

- Alloy 260, also known as cartridge brass or ammo cartridge brass. Because of its ability to withstand cold working, it is a suitable material for manufacturing products such as ammunition, automobiles, fasteners, and hardware, etc.

- Alloy 272, which contains 33% zinc. This type of brass is commonly used in industrial and construction applications.

- Alloy 330, is well suited for applications requiring high machinability. With its low lead content, it is the best choice for cold working and is often used in pipe production.

- Alloy 353, also known as clock brass, is often used for precision components such as watch parts due to its excellent machinability.

- Alloy 360, is the most common type of brass and is also known as free-cutting brass. This alloy is featured by excellent formability and machinability, making it suitable for soft brazing and soldering operations. It is widely used in a variety of fasteners, fittings, valves, and hardware components.

- Alloy 385, also known as architectural bronze, is ideal for building and construction applications. It is available in a variety of extruded and drawn shapes, including handrail molding, angles, square tubing, channels and more.

- Alloys C48200-C48500, belong to leaded naval brasses suitable for machining. These alloys are usually round in shape.

- Alloy 464, also known as naval brass, is popular for its resistance to corrosion and ability to handle temperature changes, allowing it to be used in both cold and hot forming processes. In addition, it is suitable for soldering, bending, thermoforming, drawing, and brazing.

Bronze Alloys

Various bronze alloys are also available depending on their composition, the most common types of which are:

- Alloy 863, Manganese Bronze offers high strength and corrosion resistance, making it ideal for heavy-duty applications such as agricultural and construction equipment. Its durability ensures longevity in these demanding environments.

- Alloy 907, Tin Bronze has excellent corrosion resistance and therefore performs well in seawater. It performs well in fatigue and wear applications while offering moderate processability.

- Alloy 917, Tin Bronze is specifically designed to handle heavy loads subjected to slow and uneven motion. It is highly resistant to corrosion but requires adequate lubrication to run properly.

- Alloy 932, High Lead Tin Bronze / Bearing Bronze, used by manufacturers to make bushings, washers, and other non-pressure parts.

- Alloy 954, Aluminum Bronze is a very durable alloy with excellent corrosion resistance, good weldability, excellent high-temperature strength, high tensile strength, ductility, and yield strength.

- Alloy 955, Aluminum Bronze, is a tough non-ferrous alloy with high compressive and yield strengths, as well as impressive hardness and elongation. Resistant to seawater corrosion and high temperature. It is also easy to weld and process.

Copper Alloys

Some of the most commonly used copper alloys in rapid prototyping are:

- Alloy 101, If high electrical conductivity and ductility are required, you can choose Alloy 101 – an oxygen-free copper.

- Alloy 110, has excellent electrical and thermal conductivity, as well as ductility. It is also known as electrolytic (ETP) copper.

- Alloy 122, It shares mechanical properties with Alloy 110, but also offers excellent weldability, formability and brazing capabilities.

- Alloy 145, Tellurium Copper contains 0.4-0.7% tellurium. It also offers excellent thermal and electrical conductivity, formability and processability, and is available in rod and rod form.

Material Properties

Elemental Composition

Brass is an alloy of copper and zinc of variable composition. Brass typically contains 55% – 95% copper and 5% – 45% zinc. The exact composition of brass may vary depending on the intended application and the desired properties of the material. Ordinary brass is a copper-zinc binary alloy, and its zinc content varies widely, so its room temperature structure is also very different. In order to obtain higher strength, corrosion resistance and good casting performance, special brass is formed by adding aluminum, silicon, manganese, lead, tin and other elements to the copper-zinc alloy. Such as lead brass, tin brass, aluminum brass, silicon brass, manganese brass, etc.Bronze is the earliest alloy in the history of metal smelting. It is an alloy with tin or lead added to pure copper (red copper). The alloy of copper and tin is called bronze, so named because of its bluish color. Bronze is the earliest alloy used in history, which is a copper-tin alloy or an alloy of other elements except zinc and nickel, such as aluminum, beryllium, manganese, and silicon. Bronze originally refers to copper-tin alloy, but in industry it is customary to call copper alloys containing aluminum, silicon, lead, beryllium, manganese, etc. bronze, so bronze actually includes tin bronze, aluminum bronze, aluminum bronze, beryllium bronze, silicon bronze , lead bronze, etc. Bronze is also divided into two categories: pressure-processed bronze and cast bronze. Tin Bronze: A copper-based alloy with tin as the main alloy element is called tin bronze. The tin content of tin bronze used in industry is mostly between 3% and 14%. Tin bronze with a tin content of less than 5% is suitable for cold processing; tin bronze with a tin content of 5% to 7% is suitable for hot processing; tin bronze with a tin content of more than 10% is suitable for casting.Pure copper is known as red copper, also called purple copper. Copper is one of the few directly usable metal forms found in nature. Unlike brass, it is a pure metal. Additionally, it can be used alone or combined with other pure metals and alloys to create its alloy subset.

Corrosion Resistance

The use of bronze is very beneficial in marine applications and marine fittings because of its ability to withstand saltwater environments. But continued exposure to chlorine compounds can reduce the copper content of this metal.Brass has lower corrosion resistance than bronze, but certain brasses with high manganese content exhibit better corrosion resistance.Brass is generally more corrosion-resistant than copper due to the addition of zinc. Zinc helps form a protective barrier on metal surfaces, helping to prevent metal corrosion.Copper, on the other hand, can corrode in certain environments, especially in the presence of moisture and other substances. Over time, copper will develop a greenish-blue patina on its surface, which may provide some additional protection from further corrosion. However, in some applications this patina can also be unsightly or interfere with conductivity.In summary, bronze is more resistant to corrosion than brass, and brass is generally more corrosion-resistant than copper.

Durability

Bronze is a hard and strong metal that repels water, making it resistant to corrosion caused by water. In comparison, brass is not as durable as bronze, but it is also strong and can resist corrosion and cracking. Brass is generally more durable than copper. Because brass is an alloy made of copper and zinc, making it stronger and harder than pure copper. Conversely, copper is softer and more malleable than brass, making it easier to work with in certain applications.

Machinability

Machinability refers to how a metal responds to stress during machining processes such as turning and milling. Bronze is a stronger, harder metal but is easier to machine than brass, which is less flexible.Brass is generally better workable than copper due to its greater ductility. Brass has a lower melting point than pure copper, making it easier to work. Additionally, brass has a more uniform and consistent grain structure than copper, which can reduce tool wear and surface roughness during machining.However, the machinability of brass and copper is affected by the specific alloy and composition of the material and the type of machining technique used. Generally speaking, brass is often preferred over copper in applications where machinability is a major consideration.

Weldability

Both brass and bronze are solderable, but certain factors can affect their solderability. Leaded brass alloys are an exception. Brass with lower zinc content is easier to weld, and brass with 20% zinc has good weldability. Cast brass is somewhat solderable, while lead-free bronze alloys can crack under stress. However, SMAW can be used to carefully solder leaded phosphor bronze. Soldering copper is easier when there is no oxygen or deoxidation. Copper can be soldered using MIG and TIG techniques, and brass alloys support these methods as well as silver soldering. However, alloys containing lead are more difficult to solder, while alloys with lower zinc content are easier to solder.

Hardness

The Brinell hardness scale is one of several ways to measure hardness. According to this scale, bronze has a grade between 40 and 420, while brass has a grade between 80 and 90.A comparison of these ratings shows that bronze is generally harder than brass. As a result, bronze is also more brittle, making it more susceptible to cracking than brass. Bronze is a good choice for projects that require durability and strength. However, if a project requires workability, brass is a better choice.Brass is generally harder than pure copper due to the addition of zinc, which makes the alloy stronger. The exact hardness may vary depending on the specific composition of the brass and copper being compared. Generally speaking, brass has a Brinell hardness of about 80-90, while pure copper has a hardness of about 35-45. However, there are specialized copper alloys such as beryllium copper that are harder than brass. Overall, brass is generally considered a harder material than pure copper.

Conductivity

Bronze and brass are two copper alloys that both have low relative conductivity due to the presence of other elements. When using copper as the standard, brass has a higher conductivity of 28%, but bronze has the lowest conductivity of only 15%.Both brass and copper are good conductors of electricity, but copper has a higher conductivity than brass. Copper is preferred over brass in applications that require high electrical conductivity, such as electrical wires. However, brass remains a widely used material in electrical components due to its other desirable properties, such as corrosion resistance and workability.

Thermal Conductivity

Brass has significantly higher thermal conductivity than bronze, making it an excellent choice for heat sinks. While bronze can also be used for thermal purposes, brass is always the first choice when choosing between the two.Both brass and copper are excellent thermal conductors, but copper has a higher thermal conductivity compared to brass. The thermal conductivity of copper ranges from 385 to 410 W/mK, while that of brass ranges from 109 to 141 W/mK. This means that copper conducts heat more efficiently than brass.

Strength

Tensile Strength

Both bronze and brass are in demand because they increase tensile strength when cold worked or, in the case of brass, add more zinc. Annealed bronze has a tensile strength of 50 Ksi (350 MPa), while cold-rolled tempered bronze has a tensile strength of 92 Ksi (635 MPa). Meanwhile, annealed brass has a tensile strength of 53 Ksi (365 MPa) and cold-rolled tempered brass has a tensile strength of 88 Ksi (607 MPa).Brass is stronger and more durable than copper, which also makes it more susceptible to stress fractures. Although the ultimate tensile strength of brass is low, it can be increased by changing the elemental composition. Brass generally has higher tensile strength than pure copper. The tensile strength of brass is typically between 338-469 MPa, while pure copper has a tensile strength of approximately 210 MPa.

Yield Strength

The yield strength of bronze is higher than that of brass and ranges from 125 to 800 MPa. On the other hand, the yield strength of brass is lower and ranges from about 95 to 124 MPa.The point at which a material begins to permanently deform, known as the yield strength, is usually considered to be the highest stress it can withstand. When comparing copper and brass, it is evident that the yield strength of brass is higher than that of copper.

Shear Strength

In terms of shear strength, brass is superior to bronze, ranging from 35,000 psi to 48,000 psi. in contrast, bronze has a lower shear strength, ranging from 35,000 psi to 47,000 psi.

Formability

The softness of brass allows for greater formability than copper-tin bronze. Although brass is considered hard, it is still softer in composition than bronze. As a result, brass is easier to form, cut and file.Brass is usually easier to form than copper due to its lower melting point and higher ductility. Brass can be rolled, stretched or stamped into complex shapes with relative ease, making it a popular choice for decorative and functional applications. On the other hand, copper is typically more brittle than brass, which makes it more difficult to form precise shapes without cracking or breaking.

Melting Point

Both bronze and brass are easy to cast, but bronze has a higher melting point range of 315-1080°C, while brass has a melting point range of 900-940°C. When molding between brass and bronze, the mechanical properties required for the project should be considered. For more decorative projects, brass is a better choice, while for more resilient projects, bronze would be more appropriate.When a project requires moldability, comparing the melting points of copper and brass can help in choosing the more appropriate metal. Copper has a melting point of 1083°C (1981°F), while brass alloys have a melting range between 900°C (1650°F) and 940°C (1720°F), depending on composition. As a result, brass has a lower melting point than pure copper due to the presence of zinc in its structure.

Specs	Bronze	Brass	Copper
Thermal conductivity (20 °C)	24 W/m·K	120 W/m·K	386 W/m·K
Fatigue strength	90.0-352MPa	22-360MPa	100-200MPa
Melting point (average)	1010℃	917℃	1084.62℃
Hardness (brinnell)	40-42	55-73	35-45
Machinability (average)	33.0%	46.8%	40%
Component	Primary: copper and tin others: phosphorus, silicon, aluminum, manganese, zinc, etc.	Primary: copper and zinc other: iron, lead, aluminum, silicon, manganese, etc.	Copper
Durability	Highly durable	Highly durable	Durable
Processability	Ease	Lower	Lowest
Solderability	High	Good	High
Corrosion resistance	Excellent	Good	Lowest

Differences Between Brass, Bronze and Copper

Weight, Appearance, Price

Weight

If your project requires a lightweight metal, brass is a better choice than bronze because they have similar densities, but brass is lighter. When considering the weight of copper and brass, it is important to note that copper has a higher density of 8930 kg/m3, while the density of brass varies depending on its elemental composition, ranging from 8400 to 8730 kg/m3. Based on this, if your project requires a lightweight metal, you should choose brass instead of copper.

Appearance

An easy way to tell bronze from brass is to look at their color. Bronze usually has a reddish or dark brown color, although this may vary slightly depending on the mixture of other elements added. In contrast, brass usually has a golden hue, similar to a dark gold color. This characteristic makes it a popular material for furniture and fixtures. Copper and brass are two different materials; copper is a pure metal and brass is a copper alloy. Copper’s color is usually quite distinct, and its reddish-brown hue makes it easy to distinguish from brass. Brass, on the other hand, can take on a variety of colors depending on its elemental composition, such as golden yellow, reddish gold, or silver.

Price

The composition of bronze and brass varies depending on a range of factors, such as their copper content. The amount of copper contained in each alloy determines its market price. However, bronze is usually more expensive than brass, mainly due to its higher percentage of copper and the manufacturing technique required. The cost of brass and copper fluctuates depending on the specific grade being compared. In general, copper tends to be the more expensive option between the two. Brass, on the other hand, has a lower copper content and is therefore less expensive.

Metal	Price	Color	Weight
Bronze	Bronze is an alloy of copper and tin. Bronze is generally more expensive than brass.	Bronze has a reddish-brown color.	Bronze is denser than both copper and brass, with a density of 8.8-9.0 g/cm³
Brass	Brass is an alloy of copper and zinc. The price of brass is generally lower than that of bronze.	Brass has a yellowish-gold color.	Brass is less dense than copper, with a density of 8.4 g/cm³
Copper	Copper is a pure metal and is relatively inexpensive. The price of copper fluctuates depending on the market demand and supply.	Copper has a reddish-brown color.	Copper is a relatively heavy metal with a density of 8.96 g/cm³

Differences in Weight, Appearance, and Price Between Brass, Bronze and Copper

Advantages

Bronze

Bronze is a general term for copper-tin alloys, which can be divided into tin bronze, aluminum bronze, beryllium bronze and so on according to the different added elements. Bronze has good wear resistance, corrosion resistance and anti-fatigue properties, commonly used in the manufacture of a variety of wear-resistant parts, structural components and machine parts.High degree of corrosion resistance: bronze has high strength and low melting point (25% of tin smelting bronze, the melting point will be reduced to 800 ℃. Pure copper (copper) melting point of 1083 ℃), generally has a good corrosion resistance wear resistance, casting and excellent mechanical properties and chemical stability.Plasticity: the original meaning of bronze refers to copper-tin alloys, and later, for ease of management, all copper alloys other than white copper and brass were standardized as bronze. Several other elements, including aluminum, arsenic, manganese, phosphorus, and silicon, were added to obtain different properties to create different types of bronze alloys. These mixtures result in some of the more commonly used bronze alloys, such as leaded bronze, phosphorus bronze, aluminum bronze, silicon bronze and manganese bronze. And they are preceded by the name of the main added element to distinguish the different types of bronze. Tin bronze, with tin as the main added element, has excellent casting properties, good mechanical properties, excellent friction reduction properties, and is very suitable for the manufacture of turbines, gears, and bearings. Lead bronze, on the other hand, is applied as a bearing material now used in engines and grinding machines. Aluminum bronze has excellent wear and corrosion resistance, high strength, and is widely used in the manufacture of high load bushings, gears, marine propellers and so on. Phosphor bronze has good electrical conductivity, high elastic limit, and is very suitable for manufacturing precision springs as well as electrical contact components.

Brass

Brass is a kind of copper-based alloy with zinc or other elements added. According to the different elements added, brass can be divided into ordinary brass, special brass and casting brass. Brass has good strength and corrosion resistance and is widely used in the manufacture of various structural parts, valves and fittings.Aesthetics: With its bright and lustrous golden hue, brass has long been the material of choice and is still widely used to make drawer pulls and door handles. Brass is a beautiful natural material whose surface color changes gradually over time. Using brass as a cladding material for buildings creates a natural, varied façade that leaves a warm impression. The qualities of brass are beautifully colored, durable, and environmentally friendly, giving people a pleasant surprise.Recyclability: Brass is not ferromagnetic and is therefore easier to recycle.Durability: By adding different metals to the alloy, brass can display a range of properties, such as greater corrosion resistance when manganese is present, or variable melting points. The ratio between copper and zinc will determine its type. If the zinc content is higher, the brass will become stronger and more pliable, while a higher copper content will make the brass more electrically conductive.In addition, due to its low melting point, ductility (with hand tools and modern tools), brass has been widely used for carving and making implements milling and lathe), rigidity and excellent thermal and electrical conductivity. Brass with a high copper content is more golden and softer in color, while brass with a low copper content and a high zinc content is more silvery and harder.

Copper

Pure copper, also known as purple copper, is one of the most commonly used copper materials in machining. Pure copper has excellent electrical and thermal conductivity, and is commonly used in the manufacture of various electrical parts and radiators. Due to its low strength, pure copper is mainly used for occasions that do not require high strength.Outstanding thermal and electrical conductivity: copper is a suitable material for thermal equipment and electrical & electronic systems. It has good plasticity, excellent electrical and thermal conductivity, and can be applied to both hot and cold press processing, and is widely used in products such as cables, wires, and electro-etching copper for EDM. High purity red copper, fine organization, low oxygen content, no trachoma or porosity, excellent electrical conductivity, very suitable for electro-etching molds, the electrode has no direction after the heat treatment, very suitable for fine hitting.Easy to process: It has an orange-red hue and produces a slight reddish luster when just exposed. It can be machined without any manual fabrication.Antibacterial: copper is resistant to bacteria and does not degrade. In addition, it has the ability to kill bacteria when exposed to its surface. This quality makes it an excellent choice for use in food safety equipment.

Application Scenarios

Bronze

Aluminum Bronze Alloys

Aluminum bronze alloys are known for their excellent durability and corrosion resistance. These alloys are used in a variety of applications including:

- Tail cones

- Wearing rings

- Shipboard materials

- Gears for large parts

- Forming rolls and molds

- Pump and valve components

- Propeller system components

- Hub bodies for marine or naval applications

Tin Bronze Alloys

Tin bronze alloys offer excellent wear resistance, but they are typically more expensive. Common applications for these alloys include:

- Impellers

- Bushings

- Bearings

- Piston gears

- Steam fittings

- Hydraulic Components

Manganese Bronze Alloys

Manganese bronze alloys have a high proportion of zinc and can be used as an alternative to traditional brass materials. Due to their robustness, these alloys are ideally suited for high-pressure tasks, for example:

- cams

- worm gears

- nuts

- Steel mill nuts

- Flanges

- Bushings

- Forming rolls and molds

- Valves with larger stems

Brass

Red Brass

Red Brass is a malleable brass alloy that can be easily molded or forged to meet specific requirements. It is particularly suitable for creative activities due to its distinctive dark bronze hue. Red brass has a wide range of uses, including:

- Badges

- Jewelry

- Grilles

- Plumbing fixtures

- Automotive components

- Marine Hardware

- Gears and Pulleys

- Door handles

- Musical Instruments

- Decorative trim

- Architectural fascia

Brass

Brasses have medium strength, good corrosion resistance and in some forms high ductility. As such, they can be used in a variety of applications:

- Industrial: heat exchangers, pump cylinders, screens, pumps, pneumatic conveying systems, soundproofing equipment, springs, chains, bushings, power cylinders, bead chains, and piping for instruments and machines.

- Automotive: electrical connectors, heater cores, thermostats, radiator cores, radiator tubes, radiator tanks, fuel tanks, odometer contacts.

- Consumer Goods: watch parts, artificial jewelry, buttons, electrical outlets, lamps, push buttons, flower pots, fireplace screens, etchings, bird cages, coins, chain links, pen/pencil inserts and clips, and syringe parts.

- Architectural: grilles

- Electrical: lamps, reflectors, screw housings, terminals, flashlight housings.

- Fasteners: eyelets, screws, pins, grommets, rivets, and fasteners.

- Plumbing: traps, fittings, bathroom fixtures, plumbing fittings, plumbing brassware, faucet orifice covers.

Free Machining Brass

C-360 Brass is a low-cost alloy with good engineering properties and machinability. It is commonly used in a variety of situations:

- Industrial: faucet parts, pneumatic fittings, fluid connectors, automatic screwdriver parts, live joints, adapters, screwdriver products, gauges, valve seats, valve internals, valve stems, nozzles, pinions, gears.

- Plumbing: plumber’s brass products, faucet levers, faucet seats, pipe fittings.

- Construction: locks, hardware, fittings.

- Fasteners: bolts, nuts, screws.

- Consumer: hot combs.

Copper

Pure copper can be used to make components and items for plumbing, roofing, industrial purposes, and electrical appliances.

- Radiators and heat exchangers

- industrial machinery

- building components

- Telecommunication components

- Anti-biofuel assemblies in submarines

- roof

- Plumbing

- Electrical wiring

- vacuum tube

- electric motor

Technique Flow

The typical technique flow of copper machining includes the following steps:

1. Casting: According to product requirements, copper is melted and poured into molds to make castings of the desired shape.

1. Forging: The casting is heated and then forged to increase its strength and reduce its size.

1. Cutting: Copper is accurately processed through turning, milling, drilling and other machining methods.

1. Surface treatment: The finished copper material is subjected to surface treatment, such as polishing, chromium plating, etc., in order to improve its appearance quality and corrosion resistance.

1. Assembly: The finished copper material will be assembled according to the product requirements to complete the final product.

Trend

With the continuous development of science and technology, the development trend of machining copper is mainly reflected in the following aspects:High strength: In order to meet the ever-increasing product quality and performance requirements, the strength and carrying capacity of copper has become the focus of attention. Through the optimization of alloy composition, improve the processing technology and other means to continuously improve the strength and carrying capacity of copper.Lightweight: With the continuous development of automobile, aerospace, and other fields, lightweight has become an important means to improve product performance and reduce energy consumption. The use of high-strength lightweight alloys, optimized structural design, and other means to achieve lightweight copper.

Tips for Choosing the Right Material for Your Project

Choosing the right metal is critical when designing and manufacturing a high-quality part or product. Bronze, brass, and copper have distinct differences that must be considered. When choosing sheet metal materials, keep in mind some of the essential differences among these metals:

- Brass and copper, while inherently durable, differ in their flexibility. Copper with a pure oxygen-free content is the most pliable, highly ductile and electrically conductive. Copper has excellent electrical conductivity, while brass has better workability.

- For general use, brass is usually preferred because of its versatility. If cost is an important factor, then it is better to choose brass over copper because brass is cheaper. However, if you need electrical conductivity, copper would be favorable.

- Brass is commonly used for a variety of purposes, such as musical instruments and door handles, mainly because of its low friction properties. On the other hand, bronze is ideal for marine applications due to its excellent resistance to salt water.

- The utility and application of the component will play an important role in choosing the metal. Brass is a great choice when you need electrical conductivity, while bronze is ideal for saltwater applications due to its corrosion resistance. Bronze is also more durable and resilient, making it suitable for applications that require durability and stress resistance.

- Bronze is a best choice for occasions requiring high strength and wear resistance.

- Bronze is a best choice for occasions with high corrosion resistance requirements.

- Bronze with better high-temperature performance such as aluminum bronze or beryllium bronze is ideal for high-temperature environments.

Metal Fabrication Technology, Preferred ZINTILON Technology

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