Steel vs. Aluminum: How to Make the Best Choice for Your Product Design

There are many different steel and aluminum alloys (Image source: Internet)

Aluminum vs. Steel: Factors to Consider

While there are many different steel and aluminum alloys, each with its specific properties, there are some key differences between the two metals. This section compares some of the most important physical characteristics of steel and aluminum.

1. Weight

If you ask someone which metal is lighter, most people will correctly say aluminum. Steel’s high strength comes at the cost of a much higher density. In fact, for two pieces of equal volume, steel can be as much as three times the weight of aluminum.

2. Strength

Strength is often one of the first properties considered when selecting a material, especially in high-stress applications. Generally speaking, steel is stronger than aluminum. That said, once the lighter weight of aluminum is factored into the equation, aluminum comes out on top with a superior strength-to-weight ratio. Identifying which metal has the better strength for your application will depend on your design’s flexibility. For example, a larger aluminum part may offer more strength at a lower weight than the steel alternative.

Steel products (Image source: Internet)

3. Malleability

Another downside of steel’s high strength is that it is harder to work it into different shapes than aluminum, especially if the shape is complex. This can be somewhat overcome by heating the steel to very high temperatures, but this adds cost and can compromise other properties. On the other hand, aluminum is relatively easy to form while either cold or hot and is ideally suited for manufacturing processes such as extrusion and rolling.

4. Thermal Conductivity

Aluminum is generally a much better thermal conductor than steel and is often used in applications where heat dissipation or distribution is required, such as in heat sinks.

Các sản phẩm tản nhiệt do KIMSEN sản xuất

>> Find out more information about KIMSEN's heat sinks

5. Corrosion Resistance

Plain carbon steel has poor corrosion resistance. It rusts easily and will continue to corrode if exposed to the elements. Aluminum, on the other hand, forms a protective oxide layer on its surface that acts as an inert barrier against further oxidation. So long as the aluminum isn’t exposed to an environment that causes it to break down, it will continue to provide excellent corrosion resistance. It’s worth noting that steel can be made highly resistant to corrosion if a minimum of 11% chromium is included in its alloying elements, making it “stainless steel.” Stainless steel, however, is more costly than plain carbon steel, and other physical properties of the steel may be affected.

6. Cost

The cost of the material will naturally be a significant factor in which you choose for your project. Since the price of both of these metals will fluctuate with the market and the specific alloy, it is hard to say that one will be cheaper than the other in every context. However, it is commonly accepted that, pound for pound, carbon steel is generally less expensive than a comparable aluminum alloy.

7. Physical Properties Comparison

The following table compares specific values for the physical properties of steel and aluminum. For this purpose, we’ve compared a medium carbon steel and general aluminum alloy.

Applications for Aluminum and Steel

When trying to choose between steel and aluminum for your specific project, knowing the common areas of application for each of them could be very helpful. The following table shows the most common uses of these metals in different industries.

Aluminum's application in infrastructure (Image source: Internet)

Should You Choose Steel or Aluminum for Your Project?

Whether to choose steel or aluminum for your project will ultimately depend on your project’s characteristics, the forming process, and your budget. For example, if strength and durability are the most important attributes for your design, and the shape is not too complex, perhaps a steel alloy is the better option. On the other hand, if you need a good strength-to-weight ratio, corrosion resistance, and the ability to form a unique shape, aluminum is probably the better choice.

Source: gabrian.com