Aluminium vs Steel: Understanding the Differences
Aluminium and steel are the most commonly used metals in various industries, applications, and sheet metal fabrication projects. This is because of their unique properties which makes them more durable. What’s more, they are also widely produced which makes them easier to source.
But when it comes to aluminium vs steel, which one is better?
Well, the answer depends on a number of factors; mostly their difference in properties. Read on to find out what these differences are, as well as the common applications of both metals in sheet metal fabrication services.
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Aluminium vs steel: what are the differences?
There are several differences between aluminium and steel. Let’s take a look at their properties in more detail so we can understand how both compare.
Physical state
Aluminium: The most abundant element on earth, aluminium is light and silvery-white in its appearance. Thanks to its aesthetic appeal – it’s ideal for use in kitchen appliances.
Steel: Steel’s physical state will vary depending on the treatment it undergoes. Typically, it comes in a range of colours. For example, steel containing heavy amounts of carbon will be dark brown in appearance, whereas stainless steel is shiny and silver.
For more information on sheet metal finishes, take a look at our blog.
Maleability
Aluminium: Aluminium is the second most malleable metal, so it can be moulded into different shapes. In terms of malleability, aluminium is a more suitable option than steel.
Steel: Steel is still highly malleable, meaning it can be shaped into many different forms. Because of this malleability, it’s also easy to join steel together to make intricate shapes.
Ductility
Aluminium: Aluminium is the sixth most ductile metal in the world. So, it can be shaped into forms without risk of breaking, but there are still better alternatives out there.
Steel: Generally, steel is able to be ductile, but this depends on the variation you choose. Ultimately in terms of ductility, aluminium would be a better option.
Conductivity
Aluminium: Aluminium’s electrons can easily move between atoms making it a strong conductor of electricity.
Steel: Steel does conduct heat and electricity to a certain degree, but again, it depends on the variation of steel used. For example, stainless steel tends to be a poor conductor of heat as a result of its alloy structure.
Density
Aluminium: The density of aluminium is about 2,710kg/m3, a fairly low amount, which is why it is lightweight and easy to move.
Steel: Plain steel has a density of 7.85g/cm³, 7850kg/m³, making it a fairly dense metal. This makes it a sturdy and durable material for use in the construction and manufacturing of heavy-use objects.
Luster
Aluminium: Aluminium has a dull lustre, typically the result of a thin layer of aluminium oxide.
Steel: Whether steel has a lustre depends on the type you use. Mild and stainless steel have a shiny finish, whereas carbon steel does not.
Melting point
Aluminium: Aluminium has a melting point of 660 Celsius (°C).
Steel: Steel has a melting point of 1,205-1,370 Celsius (°C).
Tensile strength
Aluminium: The tensile strength of aluminium is 90 MPa but this can be increased to over 690 MPa for some heat-treatable alloys.
Steel: The tensile strength of steel depends on its variation but typically, high-grade steel has a high UTS of approximately 1,000 megapascals (MPa).
Corrosion resistance
Aluminium: Aluminium and its alloys have significant resistance to corrosion. But, when submerged in water it can be exposed to higher chances of corrosion.
Steel: Steel containing carbon is not corrosion-resistant, due to the higher chances of it experiencing oxidation. Stainless steel however is corrosion-resistant.
Overall, is aluminium stronger than steel?
Pure steel in general is stronger than aluminium, mostly because it is a much denser material. Furthermore, as aluminium is a high conductor of electricity, it is less resistant to corrosion, making it a weaker metal.
But, when considering which of the two metals is stronger, sometimes weight can factor into the equation. For example, aluminium has a better strength-to-weight ratio than steel, meaning that although more aluminium is needed to support the same load as steel, it would weigh much less.
Is aluminium cheaper than steel?
Whether aluminium is cheaper than steel depends on the type of steel you purchase.
For example, steel varieties like mild steel and carbon steel are cheaper than aluminium. However, stainless steel carries a heavier price tag than aluminium.
Aluminium: common applications and uses
The applications and uses for aluminium vary, but most commonly they are used in the following areas:
Infrastructure
As it is a low strength metal, aluminium is not an ideal material for building physical structures. However, it does have other benefits that make it desirable for the industry. For example, aluminium is commonly used to make roofing materials.
This is generally more specific to Australia where many people opt for roofing types such as tiles and shingles. As it is corrosion resistant, it makes it an ideal option to protect a home from severe weather conditions. What’s more, thanks to its lightness and thinness it contains very little heat – keeping a home cooler in the summer months.
Manufacturing
Aluminium is widely used in the construction industry for machine bearings. These are systems that assist an objects’ rotation within different types of machinery, including automobiles, planes, and electric generators.
Aluminium is an ideal option for machine bearings because of its corrosion resistance, which helps to minimise damage and ultimately saves money on maintenance, repair, and replacement costs.
Transportation
It has been estimated that 25% of the aluminium used in transportation is used in road and rail commercial transport. Most uses of aluminium in this industry come in the form of rolled products (sheets and plates) and extrusions, as it is easy to shape and bend.
It’s also a common choice for aircraft construction, mostly because of its resistance to UV damage.
Appliances
Aluminium is a significant conductor of heat, which makes it a great choice for the manufacturing of kitchen appliances that rely on generating heat, such as ovens, microwaves, and radiators.
It’s also used in handheld kitchen equipment, including pots, pans, and oven trays, because of its lightweight properties that make it easy to lift by an average user.
Steel: common applications and uses
Steel is also used in the same industries as aluminium, but they have different purposes. For example, in:
Infrastructure
Steel is commonly used in the construction of certain types of infrastructure. This pertains but is not limited to, bridges, railways, train stations, and airports.
Thanks to its significant strength, versatility, and cost-effectiveness, it’s a popular option for the construction of the above pieces of infrastructure.
Manufacturing
As mentioned, because of its high tensile strength and low cost, steel is a popular choice in the manufacturing industry.
For example, in ship manufacturing, high tensile steel is typically applied to areas of the ship that are exposed to larger amounts of mechanical stress, as well as the deck and bottom regions of larger tankers.
Transportation
In the transportation industry, most journeys and means of traveling are made possible because of steel. In cars, steel is a common choice for machine bearings and pipework, as well as car rims.
It’s also used in many car engines because it can withstand high temperatures and varying pressures.
Appliances
When it comes to kitchen appliances, stainless steel is predominantly used because of its finish, as well as its higher levels of resistance to types of corrosion, such as rust.
But, pure steel is also used within the industry, predominantly for washing machines, as it makes them easier to repair and maintain than those using plastic components.
Aluminium vs steel: FAQs
Aluminium vs steel – which lasts longer?
Aluminium and steel are both known for their durability and strength. Whether one lasts longer than the other also depends on the specific applications either are used in. However, aluminium will most likely last longer than regular steel because of its corrosion resistance.
Steel is heavier and stronger than aluminium, making it a better choice for heavy duty projects and purposes. Meanwhile, aluminium is more flexible and bendable than steel, making it ideal for projects involving shaping.
Which is better for an individuals’ health – aluminium or stainless steel?
Exposure to steel and aluminium will not be extremely harmful for an individual to experience, but it does depend on what the metal is being used for.
For example, when it comes to food preparation and cooking, stainless steel is generally considered to be a safe option. This is for a number of reasons, including:
- Reactivity: Aluminium is more likely to react with acidic foods if used in excess, which ruins the taste of food and affects nutritional value.
- Oven safety: Stainless steel is oven safe whereas aluminium isn’t.
- Dishwasher safety: Stainless steel is dishwasher safe whereas aluminium isn’t.
Choose Salamander Fabrications for Accurate Results
Your business might need sheet metal fabrication services, but that doesn’t mean that sourcing them has to be a chore. In fact, the experts at Salamander Fabrications can help provide you with the advice, guidance, and solutions you need to get your projects off the ground.
If you want to get started with metal sheet fabrication, or simply want to find out more about our services, get in touch with our team of experts today.
