Brass is an alloy of copper and zinc, golden yellow in colour, easy to machine and widely used in taps, valves and electrical parts. Bronze is an alloy of copper and tin, harder and more resistant to wear and seawater, which is why it is used in bearings, gears and marine parts. The difference between brass and bronze lies in the second metal in the alloy, and that is what determines their colour, properties and uses.
This guide explains what each alloy is, how they differ, what each one is used for and when to choose one or the other. At the end you will also see what happens to them when they end up as scrap.
What is brass?
Brass is an alloy of copper with zinc. The zinc content is usually between 5% and 45%, and that proportion changes the material considerably: with little zinc, brass is reddish and very ductile; with more zinc it turns yellow, harder and better suited to forging and machining. Many brasses also contain small amounts of lead, tin, aluminium or arsenic to improve machinability or corrosion resistance.
What makes brass so common in industry is its balance: it machines very well, resists corrosion in fresh water and in the atmosphere, conducts electricity and heat well, has an attractive golden finish and is cheaper than bronze. It melts at around 900–940 °C, lower than copper, which makes casting and hot stamping easier.
Most common types of brass
| Type | Approximate composition | What it is used for |
|---|---|---|
| 70/30 brass (CuZn30) | 70% copper, 30% zinc | Deep drawing, ammunition cases, heat exchanger tubes |
| 60/40 brass (CuZn40) | 60% copper, 40% zinc | Hot forging, stamped parts, sheet |
| Free-cutting brass (CuZn39Pb3) | Copper and zinc with 2–3% lead | Turned parts, pipe fittings, screws and fasteners, locks |
| Naval brass (CuZn39Sn1) | Copper and zinc with 1% tin | Fittings and parts in contact with seawater |
| Dezincification-resistant (DZR) brass | Copper and zinc with small additions, such as arsenic | Plumbing and drinking water |
| Tombac or red brass | 85–95% copper | Costume jewellery, medals, decorative pieces |
What is bronze?
Bronze is a copper alloy whose second element, in classic bronze, is tin, usually between 3% and 20%. Copper alloys with aluminium or silicon as the main alloying element are also called bronzes, and phosphor bronze is a tin bronze with a small addition of phosphorus. Bronze is harder than brass, stands up better to friction and marine corrosion, and its colour ranges from reddish brown to golden brown.
If you are looking for the composition of each type of bronze, its colour or how it compares with copper, you will find it in the guide to copper and bronze.
What is the difference between brass and bronze?
Both are copper alloys, but zinc and tin give them opposite characters. Brass is the material for parts that have to be machined in large runs and must withstand water and moisture; bronze is the material for parts that work under friction, under load or in salt water.
| Characteristic | Brass | Bronze |
|---|---|---|
| Main alloying element | Zinc | Tin (or aluminium or silicon) |
| Colour | Golden yellow | Reddish brown or golden brown |
| Hardness | Medium | Higher |
| Machinability | Excellent, especially with lead | Good, varies with the alloy |
| Wear resistance | Moderate | High, with low friction against steel |
| Corrosion | Good in fresh water; can suffer dezincification in aggressive water | Excellent, including in seawater |
| Electrical conductivity | Good, higher than most bronzes | Lower |
| Melting point | About 900–940 °C | Around 850–1,050 °C, depending on the alloy |
Dezincification deserves an explanation: in water containing chlorides, or other very aggressive water, the zinc in brass can dissolve and leave behind a porous, brittle copper structure. That is why DZR brasses are used in plumbing, while for marine use naval brass, or simply bronze, is preferred.
What is brass used for?
The uses of brass have a common denominator: precision parts, produced in large runs, that must resist moisture and look good.
| Sector | Typical brass parts | Why brass |
|---|---|---|
| Plumbing and gas | Taps, valves, stopcocks, pipe fittings | It machines well and resists water |
| Electrical | Terminal blocks, terminals, plug pins, connectors | Good conductivity and easy to turn |
| Locks and ironmongery | Locks, keys, hinges, handles | Durable, does not rust like steel and has a good finish |
| Musical instruments | Trumpets, trombones, tubas, saxophones | Easy to work as sheet and has a good tone |
| Ammunition and industry | Cartridge cases, heat exchanger tubes, stamped parts | Ductile enough for drawing and forming |
What is bronze used for?
Bronze is used where brass would fall short: parts that rub, carry loads or spend their working life in salt water.
| Use | Typical bronze parts | Why bronze |
|---|---|---|
| Mechanical | Bearings, bushes, worm wheels, gears | It resists wear and has low friction against steel |
| Marine | Propellers, seawater valves, pumps | Excellent resistance to marine corrosion |
| Electrical | Springs, contacts, phosphor bronze connectors | Elasticity and fatigue resistance |
| Industrial safety | Non-sparking tools for ATEX zones (explosive atmospheres) | Aluminium bronzes produce hardly any sparks when struck |
| Art and sound | Sculptures, bells, cymbals | It casts well in moulds, develops a stable patina and has a good tone |
When should you choose brass and when bronze?
Choose brass when you need turned or stamped parts in large runs, with a good finish and at a competitive cost: taps, connections, terminals, fittings. For drinking water, specify dezincification-resistant brasses with a low lead content.
Choose bronze when the part will work under friction, repeated loads or in seawater: a bush turning on a steel shaft, the worm wheel of a reduction gearbox or a valve on a ship. Bronze is usually more expensive, because tin costs more than zinc, but in those conditions it lasts much longer and pays for itself.
Can brass and bronze be recycled?
Yes, and without losing their properties: they are melted down and become new brass and bronze. The condition is that they arrive separated by alloy: each foundry works to a specific composition, and the tin from bronze mixed in with brass, or the zinc from brass mixed in with bronze, throws it off. We explain how to tell them apart and prepare them in the guide to identifying brass and bronze in scrap.
At Alberich we buy brass, bronze and zamak, both from industry and from our own dismantling projects, and sort them by alloy before sending them to specialist foundries. You can see how we handle them on our brass and bronze page, and the rest of the materials in what we buy. And if you are comparing these alloys with others, there is an overview in the guide to metal alloys.
Frequently asked questions
Does brass rust?
It doesn’t rust the way iron does, but over time it darkens and loses its shine, and in damp environments it can develop greenish stains. This is a surface layer that can be cleaned off without damaging the part.
Does brass contain lead?
Some brasses do. Free-cutting brasses contain 2–3% lead so that the swarf breaks into short chips and the part turns more easily. For parts in contact with drinking water, brasses with very little or no lead are used.
Which is more expensive, brass or bronze?
Generally bronze, because tin is considerably more expensive than zinc. As scrap, both are valued on their copper content and on how well separated they arrive.
Is brass magnetic?
No. Neither brass nor bronze sticks to a magnet. If a golden-looking part does stick, it is brass-plated steel or has steel parts inside.
If you have brass or bronze to recycle, tell us what the material is and how much you have, and we’ll give you a valuation.
