Aluminum Vs Steel, What is difference and Which is better for your project?

When it comes to manufacturing, there are all kinds of materials to work with. The two most commonly used metals are Aluminum and steel. But what’s the difference? Which approach is better for your particular project? In this blog post, we’ll compare and contrast Aluminum and steel, so you can make an informed decision about which material is best for you.

What is Aluminum?

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Aluminum is a metal element with the element symbol Al and atomic number 13. Its elemental substance is a silver-white light metal. It’s malleable. Commodities are often made in rod, flake, foil, powder, ribbon, and filamentous form.

Aluminum was discovered in 1827 by a German chemist named Wohler. Aluminum is abundant on Earth. After oxygen and silicon, it is the third most abundant metallic element in the Earth’s crust. It is nearly twice as abundant as iron and nearly a thousand times as abundant as copper.

Aluminum has special chemical and physical characteristics and is one of the most commonly used industrial metals; not only is it lightweight, a strong texture, but it also has good elasticity, electrical conductivity, thermal conductivity, heat resistance, and nuclear radiation resistance, is an important basic raw material for the development of manufacturing.

What is steel?

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Steel is an alloy of iron with typically between 0.02% and 2.04% carbon by weight.

According to the different classifications of carbon mass fraction in steel: carbon mass fraction less than 0.25% for low carbon steel; Carbon mass fraction of 0.25%-0.60% for medium carbon steel; The mass fraction of carbon 0.60% to 2.04% is high carbon steel.

The chemical composition of steel can have great changes, only containing carbon elements of steel called carbon steel (carbon steel) or ordinary steel; In practice, steel often contains different alloying elements, such as manganese, nickel, vanadium, and so on, They are called alloy steels.

What are the Differences Between Aluminum and Steel?

Aluminum Vs. Steel #1: Color

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Aluminum will not rust in the air, only natural oxidation, silver or dark gray color; the natural surface of the steel is black or rust.

Aluminum Vs. Steel #2: Density

Aluminum has a density of 2.7 g/cm3, while steel has a density of 7.8 g/cm3.

Compared to Aluminum, steel is much denser, which causes the weight of steel to soar. Mild steel is lighter than carbon steel, but Aluminum is much lighter anyway. So in terms of weight, Aluminum is better than steel; it is a very light but strong material.

Aluminum Vs. Steel #3: Strength

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In most cases, steel is much stronger than Aluminum. The carbon in steel makes it hard, and the higher the carbon content, the harder it becomes and the less ductile it becomes.

Aluminum is resilient metal, it is not as strong as steel, but it is far more flexible and malleable, which is why aluminum foil can be made very thin.

Aluminum Vs. Steel #4: Melting Point

Aluminum has a melting point of 660°C, while steel has a melting point of 1,500°C. This means that Aluminum can be melted and cast much easier than steel.

Aluminum Vs. Steel #5: Heat-conducting Property

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Aluminum generally conducts heat well, so it is often used as a heat sink for computers and as a cooling system for vehicles. Steel does not conduct heat well. However, it has a higher melting point than Aluminum and can be used over a wider temperature range.

Aluminum Vs. Steel #6:  Electrical Conductivity

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Steel conducts electricity poorly; Aluminum is very desirable metal, it is a good electrical conductor and is known for its conductive properties. Because of its lightweight characteristics and corrosion resistance, it is commonly used in high-voltage overhead power lines, automotive radiators, and air conditioning units.

Aluminum Vs. Steel #7: Corrosion Resistance

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Aluminum has high oxidation and corrosion resistance, mainly attributed to its passivation layer. When Aluminum is oxidized, its surface will turn white, and sometimes pits will appear. But in some extremely acidic or alkaline environments, Aluminum can corrode quickly, with disastrous results.

Common steel is prone to rust, especially when exposed to damp or salty air. Therefore, it is necessary to spray paint or powder coat the steel to prevent rust and corrosion.

Stainless steel consists of iron, chromium, nickel, manganese, and copper. When chrome is added, stainless steel has excellent corrosion resistance.

There are many ways to improve the corrosion resistance of steel, including:

  • Adding chromium to form stainless steel

  • Adding aluminum or silicon to form an aluminum-silicon alloy

  • Adding copper, nickel, or other metals to form an alloy steel

  • Applying a coat of paint, powder coating, or other surface of the steel.

  • Galvanizing the steel by coating it with zinc

  • Electroplating the steel with a more corrosion-resistant metal

  • Applying a thin film of oxide to the surface of the steel.

Aluminum Vs. Steel #8: Magnetic

Typical steel devices are attracted to magnets, while Aluminum has almost no magnetism.

Aluminum Vs. Steel #9: Weldability

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Aluminum can be welded using a variety of methods, but it is more difficult to weld than steel. Steel can be joined using MIG or TIG welding, and Aluminum can also be joined using these methods. However, the process is more complicated and requires more expertise.

Aluminum Vs. Steel #10: Recyclability

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Aluminum is lighter and has a lower carbon footprint than steel; it is more environmentally friendly. Aluminum can be recycled indefinitely without losing its properties, while steel can only be recycled a few times before it loses its strength.

Aluminum Vs. Steel #11: Cost

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The production of ordinary steel needs to process iron ore to get iron and then purified by different smelting methods;

The production of Aluminum requires the corresponding ore to be converted into alumina and Al2O3 after several reactions, and then the Aluminum can be obtained by high-temperature melting and electrolysis. The process of producing Aluminum is more complicated than that of producing steel, so the raw material price of aluminum is higher than that of ordinary steel.

Aluminum Vs. Steel #12: Applications

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Aluminum alloy is widely used in aviation, aerospace, automotive, machinery manufacturing, shipping, and chemical industry.

Steel is commonly used in the construction of bridges, tunnels, and other infrastructure projects. It is also widely used in the production of vehicles, ships, appliances, and many other consumer products.

How to Distinguish Aluminum and Steel?

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Weight Test: The most intuitive difference between Aluminum and steel is that the density difference is very obvious. Under the same volume, the heavy is steel, and the light is Aluminum.

Look At Surface: Aluminum will not rust in the air, only natural oxidation, silver or dark gray color; The natural surface of the steel is black or rusted. But be warned: if the steel is electroplated, it will be very bright.

Hardness Test:  Steel is stronger than most things in nature. And compared to steel, Aluminum is a much lower hardness, knocking the two together, and the larger wound is Aluminum.

Magnetic Test: Ordinary steel devices will be attracted to magnets, and Aluminum has almost no magnetism with a magnet test.

Measure Resistance: Use a multimeter to measure the resistivity of two materials. Generally speaking, the resistivity of Aluminum is lower in all kinds of metal materials, and its electrical conductivity is higher than that of steel.

Which is Better For Your Project?

Advantages of Steel:

  • It is a cheaper materials.
  • It has a higher melting point and can be used in high-temperature environments.
  • It is more durable and has a longer lifespan.
  • It is easier to weld than aluminum alloy.
  • It is more environmentally friendly because it can be recycled.
  • It has a higher strength-to-weight ratio than aluminum alloy.

Advantages of Aluminum Alloy:

  • Aluminum alloy is lighter than steel and has a lower carbon footprint.
  • It is more corrosion-resistant than steel.
  • It has better thermal and electrical conductivity.
  • It is more malleable and can be shaped into intricate designs.
  • It is more reflective and can be used in solar panels.
  • It has a lower density than steel, making it ideal for aviation and aerospace applications.

Which one is better for your project? It depends on what you need.

Steel will be the better choice if you need something cheap and widely available.

If you need something lightweight and corrosion-resistant, then aluminum alloy would be the better choice.


Steel is cheaper than Aluminum, has a higher melting point, can be used in high-temperature environments, is more durable, lasts longer, is easier to weld than Aluminum, is more environmentally friendly because it can be recycled, and has a higher strength-to-weight ratio.

Aluminum is lighter and less dense than steel; it is more resistant to corrosion than steel, has better thermal and electrical conductivity, is more malleable, and it can be molded into complex designs.


Q: What is stainless steel?

A: Stainless steel is an iron, chromium, nickel, manganese, and copper alloy. When chrome is added, stainless steel has excellent corrosion resistance.

Q: What is Aluminum Alloy?

A: Aluminum alloy is a mixture of Aluminum and other metals, such as copper, magnesium, manganese, silicon, or zinc.

Q: What is the Alloy Steel?

A: Alloy steels are iron-based alloys that contain one or more elements in addition to carbon, such as chromium, manganese, molybdenum, silicon, nickel, vanadium, or copper. They are stronger and harder than plain carbon steels.

Q: What is the difference between Stainless Steel and Aluminum Alloy?

A: The density of aluminum alloy is about 2,700 kg/mm3, and that of stainless steel is 7,900 kg/mm3. Stainless steel, which is harder than Aluminum.

iThe value of finished stainless steel is higher, depending on the material: 410, 409, 443, 430, and so on belong to the cheap stainless steel. 304 and 316 are more expensive and have a lot of materials.

In general, stainless steel is much more expensive than Aluminum.


Gavin Leo is a technical writer at Aria with 8 years of experience in Engineering, He proficient in machining characteristics and surface finish process of various materials. and participated in the development of more than 100complex injection molding and CNC machining projects. He is passionate about sharing his knowledge and experience.