Brass vs Bronze: What’s the Difference and Which Should You Use?

Brass and bronze are both metals with a lot of history and a multitude of uses in the present day. They share many properties, but they also have many key differences in their composition and applications.

Rapid Metals is one of the UK’s leading metal stockists and suppliers, selling both brass and bronze. So let us explain and explore the differences between bronze and brass, the uses of brass and the uses of bronze, and why they are best suited to these applications. Let’s look into everything brass vs bronze.

Bronze vs Brass

Bronze and brass belong to the family of materials known as ‘red metals’, named for their distinctive red/brown/gold colour range.

Neither brass nor bronze are natural, pure metals. Both are manmade alloys, consisting of a pure metal mixed with another. The main constituent of both bronze and brass is copper – this is what gives them their similar colour and their shared properties.

Brass is an alloy of copper and zinc, usually in ratios of about two-thirds copper to one-third zinc.

Bronze is copper with the addition of around 12 per cent tin.

Bronze is by far the more ancient material, having first been made at least 6000 years ago and giving its name to the Bronze Age of human history when it was the economically and culturally dominant material.

Although there is evidence for brass existing since prehistory, it was not used in significant amounts until the Roman period. Exactly how brass was made was not fully understood until the Renaissance, and modern brass was not made by directly combining copper and zinc until the 1500s. Before this time, it was considered either a form of bronze or a variety of yellow copper.

Both metals can have other elements added to their mixture (beyond the copper and tin or zinc that are their basic defining feature) to adjust their exact properties and suit them to specific purposes – these can include lead, silicon, manganese, aluminium, arsenic and phosphorus.

Difference Between Brass and Bronze

Because of their shared high copper content, both bronze and brass offer good workability, precision and corrosion resistance. They have similar melting points. They both boast excellent electrical and thermal conductivity, and both have low friction, even by the standards of other metals. Both have a colourful, attractive appearance when not weathered.

When comparing brass vs bronze, brass is a generally ‘softer’ and less durable metal than bronze, which gives it better ductility and malleability for forming into intricate shapes or being machined into precision components.

It’s easiest to contrast the relative properties of brass vs bronze if we put them in a table:

Some Cases of Brass vs Bronze

Due to their very similar properties, there are plenty of applications where both metals are generally suited to the task. Therefore, the choice comes down to the balance of each metal’s specific properties or their relative costs.

For instance, because bronze resists corrosion to an even greater extent than brass, it is often used in plumbing fittings that are safety-critical. Fire hydrants or main water valves may not be moved for long periods of time, but they have to be reliable when needed, so bronze is an ideal material. Less vital or more frequently used taps and valves can use less expensive brass.

While brass resists many forms of corrosion, it is not resistant to saltwater or applications with high temperatures. These can cause the zinc to leach out of the metal, leaving only the soft copper. Special varieties of brass that resist this effect have been produced but are more expensive than standard brass. Therefore, bronze is more commonly used in these applications, except in specific cases where brass is superior, such as for its ductility, malleability or machineability.

The Uses of Brass

Because of its combination of precision, malleability, machineability and low friction, brass is widely used for making mechanical components and similar intricate parts, especially those with moving elements. Examples include mechanical watches, door locks, hydraulic valves and various types of bearings. Brass is especially common in model engineering, because it can be easily worked to levels of great precision and produce detailed, functional parts even on a small scale.

The ductility of brass, plus its corrosion resistance, makes it a very common selection for plumbing and piping. Moving fixtures such as taps, valves and stopcocks are often made of brass, both for precision and because they won’t seize.

Brass boasts high electrical conductivity, and so brass components are often found in electrical components such as plugs, switches and connectors. The machineability, ductility and corrosion-resistance of the metal are also beneficial properties here.

Good thermal conductivity means that brass is a common choice for radiators, condensers, coolers and other heat exchangers. This is especially the case where corrosion resistance is a key consideration, and weight does not have to be minimised.

While bronze gave its name to a cultural age, brass has become the name for an entire family of musical instruments. Here again, the ductility and malleability of brass, combined with its acoustic properties (which can be altered with different specific copper/zinc ratios) and even its appearance, make it an ideal choice.

The Uses of Bronze

Bronze is hard and tough, but not especially ductile or malleable. This makes it well-suited to manufacturing items that have to be precise and durable. Being relatively brittle, it is not best used for components or items that must bear heavy (especially fluctuating) loads and torsional or compression forces.

Bronze has other distinct properties – when cast, molten bronze expands slightly just before it sets. This helps fill the mould and can define even small details of the casting with accuracy and precision (in a way that, for instance, cast iron cannot). It then contracts as it cools, making it easier to remove the finished product from the mould without damage or distortion.

Combined with bronze’s relatively low cost, relatively low melting point and good corrosion resistance, this is why it has long been a popular material for making sculptures, statues, medals and coins.

These same properties also make bronze ideal for some key mechanical and engineering uses. Because bronze doesn’t corrode and degrade in salt water (as brass does), one of the major uses of bronze is for marine parts and fittings. Ship propellers are commonly made of manganese bronze, since the material has the durability, weight and cost levels required while being ideal for casting into the complex shapes needed for the blades and hub. Ships and dockyards will also use bronze for items such as hatches, winches, capstans, bollards, valves and other critical items.

Bronze’s low friction, precision and corrosion resistance also make it ideal for bearings and bushings where peak loads are low and the metal isn’t under forces where its brittleness becomes an issue. Some forms of bronze (especially those with added lead) are described as ‘self-lubricating’, due to their low inherent friction.

Brass and Bronze from Rapid Metals

Rapid Metals stocks both brass and bronze, providing the materials that all kinds of customers, from manufacturers to tradespeople to hobbyists, need.

Our brass comes in a variety of grades, depending on the profile, to give you the perfect metal for the job. These types of brass offer superior machineability on top of all the other amazing qualities that brass brings. Our brass is available in angle and flat bar, hexagon, round or square profiles, round tube and sheet – all to a large selection of dimensions and cut to exactly the length you require. For more information about the grades of brass we offer with our different profiles, please contact us.

We sell SAE660 bronze – a leaded bronze that, as well as the general properties of bronze, has good self-lubricating characteristics and isn’t vulnerable to dezincification – as round bar in a wide choice of diameters.

No order is too big or too small for our team at Rapid Metals. Contact us to find out more or discuss your metal requirements.