Aluminium vs Steel: What’s the Difference?

Aluminium and steel are some of the most commonly used metals in the world. Titans of the construction, automotive, and aircraft industries, they are used for a virtually unlimited range of purposes. This can largely be attributed to their versatility and durability. 

Clickmetal are specialists in aluminium and steel, with over 70 years' experience within the metals industry. In this guide, we cover everything you need to know about aluminium vs stainless steel, from their strength-to-weight ratios to their many possible applications.

Is Aluminium a Metal and How Does it Differ from Steel?

Is aluminium a metal? Yes, aluminium is a lightweight, silvery-white metal known for its corrosion resistance, malleability, and high strength-to-weight ratio.

It's made by refining bauxite ore into aluminium oxide, then smelting that oxide to extract pure aluminium, which comes in various grades and forms. Aluminium is widely used in construction, transport, and manufacturing thanks to its versatility and durability.

Steel, on the other hand, is made by combining iron with carbon in a furnace. The result is a much heavier and harder material that comes in different forms, including stainless steel and mild steel. 

Stainless steel contains added chromium to improve corrosion resistance, making it ideal for kitchens, medical equipment, and architectural features. Mild steel, with a lower carbon content, is more ductile and easier to work with, commonly used in general fabrication and construction.

While aluminium and steel may look similar at a glance, they behave very differently. Understanding the difference between steel and aluminium helps ensure you choose the right material for the job.

Aluminium vs Stainless Steel: The Key Differences

Let’s not discuss these key differences, beginning with steel vs aluminium strength.

Strength

When it comes to raw strength, steel comes out on top. Its high carbon content makes it stronger and more resilient than aluminium, which is why it’s such a common component in the automotive industry.

Strength-to-Weight Ratio

There's another thing to consider when comparing aluminium vs stainless steel - weight. Although aluminium is weaker, it’s also much lighter.

The strength-to-weight ratios are 1/8 for aluminium and 1/16 for stainless steel, meaning that an aluminium structure that can support the same load as a steel structure will be bigger but weigh half as much.

Heat Resistance

Steel can resist high temperatures better than aluminium. Stainless steel has a melting point of around 1,400°C, while aluminium's melting point is around 660°C.

On the flipside, aluminium has the advantage over steel when it comes to the cold - as the temperature decreases, aluminium’s tensile strength increases, while steel turns brittle.

Malleability

Aluminium is much more flexible than steel, meaning it can be easily bent into various shapes. Steel is more rigid and will break if pushed too far. Aluminium is also very ductile and can be stretched without cracking.

Corrosion Resistance

The corrosion resistance of aluminium lends it a natural advantage. A layer of aluminium oxide protects it from exposure to air and oxygen, which are both necessary for oxidation. This means aluminium will not rust or corrode over time.

Steel has no such protection; however, some types of steel contain small amounts of alloy metals like chromium to protect against corrosion. These are known as stainless steel. Other types are galvanised in zinc for added protection.

Conductivity

Aluminium is a popular choice for electronic equipment thanks to its high conductivity. It’s why aluminium is typically used to make high voltage long distance power lines. In contrast, steel is a poor conductor.

Aluminium: Common Uses

Aluminium is used across a wide range of industries thanks to its lightweight, corrosion-resistant, and non-magnetic properties. It's easy to shape, making it ideal for manufacturing and construction.

Common uses of aluminium include:

• Windows and Doors
• Cladding and Roofing
• Automotive Parts
• Aerospace Components
• Packaging
• Electrical Applications

Its versatility makes aluminium a go-to material for modern, practical design.

Steel: Common Uses

Steel is one of the most widely used materials in the world due to its strength, durability, and adaptability. It’s found in almost every industry and plays a key role in construction, manufacturing, and engineering.

Different types of steel, such as stainless steel and mild steel, are chosen based on performance needs.

Common uses of steel include:

• Building Structures (Beams, Columns, Frames)
• Bridges and Infrastructure
• Automotive Parts and Frames
• Tools and Machinery
• Shipbuilding
• Pipelines and Tanks
• Appliances and White Goods
• Kitchen Equipment and Utensils

Steel’s reliability makes it essential in both heavy-duty and everyday applications.

What are the Benefits of Aluminium vs Steel?

When considering the difference between steel and aluminium, it’s important to weigh up the specific benefits of each. Neither material is outright better - the right choice depends on your project’s needs.

Steel is heavier and typically stronger, which makes it ideal for load-bearing structures, heavy-duty fabrication, and applications where maximum strength is critical. Stainless steel, in particular, also offers excellent corrosion resistance. Mild steel is easier to weld and shape, making it a go-to for general construction and manufacturing.

Aluminium, by contrast, is much lighter and more elastic. It’s easier to form into complex shapes and offers excellent corrosion resistance. Its high conductivity also makes it a top choice for electrical components and lightweight applications, such as transportation or cladding.

Understanding the difference between steel and aluminium helps ensure your project performs as intended. If you're unsure which metal is right for your needs, get in touch - we’re always happy to help you make the right call.

Aluminium vs Steel: Which Should You Choose for Your Project?

Aluminium, stainless steel, and mild steel each offer unique advantages, so the best choice depends on your project.

Aluminium is lightweight, corrosion-resistant, and easy to work with, ideal for transport, cladding, and electronics. Stainless steel is heavier but highly durable and rust-resistant, perfect for kitchens, medical equipment, and outdoor use.

Mild steel is strong, cost-effective, and easy to weld or shape, making it a solid choice for structural work and general fabrication.

Not sure which to pick? It comes down to performance, appearance, and environment. If you're uncertain, talk to us - we’re here to help you find the right fit.

Aluminium and Steel Cut to Size: Get in Touch Now!

Clickmetal are the UK’s premier suppliers of aluminium, stainless steel, mild steel, and galvanised steel. We cut our metals to the length you require, eliminating waste and extra labour, and have a huge range of standard and bespoke products for you to browse.

We deliver to all corners of the UK, dealing directly with both businesses and individuals. Whether you need metal for a major construction job or a small DIY project, you can trust us to provide.

Got questions about our products and services? Get in touch online or give us a call on 01794 526090 today!

Aluminium vs Steel: FAQs

Is aluminium a metal or alloy?

Aluminium is a metal. It’s a pure chemical element, though it’s often combined with other elements to form alloys for added strength or performance. These aluminium alloys are widely used in construction, transport, and manufacturing industries.

Is aluminium stronger than steel?

No, aluminium is not stronger than steel. Steel is significantly harder and more rigid, making it better suited for high-stress, structural applications. However, aluminium’s strength-to-weight ratio is excellent, which is why it's used where reducing weight is critical.

Which is more corrosion resistant: aluminium or stainless steel?

Stainless steel generally offers better corrosion resistance, especially in harsh or marine environments. However, aluminium naturally forms a protective oxide layer, which helps prevent corrosion in many everyday applications. The best choice depends on the specific environment and exposure.

Can aluminium rust like steel?

Aluminium does not rust like steel. While steel forms iron oxide (rust) when exposed to moisture, aluminium forms a stable oxide layer that protects it from further corrosion. This makes aluminium a good choice for many outdoor or damp settings.