Aluminium, Steel

Is Aluminium Harder to Weld Than Steel?

Is Aluminium Harder to Weld Than Steel?

Steel and aluminium are everywhere you look, and it’s no surprise why – both metals are incredibly strong, durable, and adaptable, making them perfect for countless building projects. However, they do have some key differences, and one of those is weldability.

If your project involves a lot of welding, this can make a big difference. A metal that’s harder to weld will take longer and require more effort, which can raise the overall cost of your project considerably.

The experts at MG Metals have been supplying top-quality metals for over 30 years, so we know all about which types work best in different situations. Below, we shed light on whether aluminium is tougher to weld than steel, and if so, why.

Is Aluminium or Steel Harder to Weld?

Generally speaking, aluminium is more challenging to weld than steel. This comes down to three main factors:

1. Heat Conductivity

Aluminium conducts heat much better than steel, which means it cools down faster. This rapid heat loss makes it difficult to achieve and maintain the optimal temperature needed to create a strong weld. Welders need to use specialised techniques, often with higher heat inputs, to counteract this heat loss.

2. Oxide Layer

Aluminium has a thin, tough layer of aluminium oxide on its surface. This oxide layer has a much higher melting point than aluminium itself and hinders the welding process. If not properly cleaned or broken through, this layer can prevent a good fusion between the base metal and the filler metal, leading to a weak weld. Techniques like wire brushing or using a special cleaning agent are employed to address this oxide layer.

3. Porosity

Aluminium is susceptible to porosity, which means tiny gas bubbles can become trapped in the weld zone during the welding process. These voids weaken the weld and can lead to cracks. Steel, while not immune to porosity, is generally less prone to it compared to aluminium. Careful technique and shielding gases are crucial to minimise porosity in aluminium welds.

What Are the Best Aluminium Welding Methods?

Aluminium may be harder to weld than steel, but that doesn’t mean it’s impossible. You can achieve strong, successful welds by using the right technique, with these being some of your best options:

  • Gas Tungsten Arc Welding (GTAW) or TIG welding: This is a popular choice for aluminium due to its precision and clean welds. It uses a non-consumable tungsten electrode and a separate filler rod. TIG welders can use Alternating Current (AC) to help break down the aluminium oxide layer for better penetration.
  • Gas Metal Arc Welding (GMAW) or MIG welding: This is a good option for thicker aluminium sections. It uses a continuously fed consumable electrode wire and shielding gas to protect the weld from contamination. MIG welders for aluminium typically require a spool gun that can handle the softer aluminium wire.
  • Electron Beam Welding and Laser Beam Welding: These are high-tech processes that use concentrated beams of energy to create very strong and precise welds. They are ideal for situations where minimising heat input is crucial, but they’re also more complex and expensive to set up.

MG Metals: The UK’s Leading Supplier for Steel and Aluminium Projects

Whether you end up choosing aluminium, steel, or another metal entirely, getting your material from a supplier you can trust is always important – and that’s where MG Metals come in.

We’re your one-stop shop for all things metal, offering a wide range of aluminium, steel, and more. We supply our components pre-cut and ready to use, saving you from the hassle of sourcing and cutting them yourself, and always strive to offer you the most competitive prices on the market.

Ready to get started? Get a free quote online or call us on 01794 521070 and turn your project vision into reality today!