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Aluminum vs Stainless Steel — 9 Main Differences

Aluminium vs Stainless Steel

If you compare aluminum vs stainless steel, you should take 9 main differences into consideration. Aluminum and stainless steel are different types of metals that may appear similar to the naked eye, but in terms of material, they differ in many ways. A way to differentiate them is to look at their appearance, aluminum tends to obtain a dull color, while steel remains just as bright.

In the following article, we will give you some of the differences that you should take into account before choosing the material for your next project.

1. Weight 

In the steel vs aluminum comparison, there is a huge difference in weight. Aluminum is not as strong as steel, but it is much lighter (it weighs almost a third of steel). This is the main reason why aluminum is chosen for manufacturing aircraft and skyscrapers.

2. Durability

There is no doubt that aluminum is a durable material, but it is not as strong as stainless steel. And while this may not be a concern in all applications, those who depend on a particular level of strength should go for stainless steel.

The reason stainless steel is stronger than aluminum is due to its higher overall density.

There are many applications, such as commercial countertops and kitchen sinks, which must be heavy in weight and highly durable, and are therefore generally made of stainless steel rather than aluminum.

3. Corrosion Resistance

Corrosion resistance is yet another important factor to consider when comparing aluminum vs stainless steel. Both aluminum and stainless steel stand out for their anti-corrosion properties, especially when compared to other metals, but still, stainless steel is less susceptible to corrosion than untreated aluminum.

The chromium in the stainless steel gives it what is essentially an invisible shield against corrosion. When it rusts, the protective chrome layer takes the brunt. When the rust is cleaned, the shield is simply renewed.

Also, depending on the grade of stainless steel, it can be made from nickel, manganese, and copper. Also, as steel is non-porous it is highly resistant to corrosion.

On the other hand, aluminum has great resistance to oxidation and corrosion, this is mainly due to its passivated layer. However, although it does not rust in the same way as steel, it does corrode.

In the same way, aluminum also has a shield, a thin layer of aluminum oxide, that protects it from rust, but rust does not protect the metal from other forms of corrosion. When it rusts, the surface turns white, and sometimes small holes can form.

In extreme temperatures and environments, aluminum can be rapidly destroyed with catastrophic results. 

However, these downsides can be ignored if aluminum is anodized or powder coated. These techniques significantly improve the corrosion resistance levels of aluminum.

4. Price

In terms of cost, aluminum is typically much more affordable than stainless steel. This factor will depend a lot on the materials used to make each metal.

However, both can be purchased at affordable prices and are highly recyclable and environmentally efficient materials.

Cost and price are always essential factors to consider when manufacturing any product. The price of steel vs aluminum fluctuates continuously based on global supply and demand, fuel costs, and the price and availability of iron ore and bauxite; however, steel is generally cheaper (per pound) than aluminum.

The cost of raw materials has a direct impact on the price of the finished goods. There are exceptions, but for two identical yarns (one in aluminum and one in steel) the aluminum one will most likely cost more due to the price of the raw material.

5. Conductivity

Aluminum offers excellent thermal conductivity. Aluminum outperforms stainless steel in both thermal and electrical conductivity. This is one of the main reasons why this metal is used in car radiators and air conditioning units.

6. Thermal properties

Compared to aluminum, steel can be used at very high temperatures because steel can become soft only at temperatures above 400 degrees.

7. Extruding and Welding

Aluminum alloys 6060 and 6063 are perfect for extruding. BK-ALPROF offers many types of aluminum profiles from these alloys - beams, tubes, angles, etc. Stainless steel is not good for extruding but is relatively easy to weld, whereas welding on aluminum is more complicated.

8. Effect on food

Both these materials are used in food preparation. They are safe, nonabsorbent, and sufficient in weight and thickness to withstand repeated washing. Because it heats and cools quickly, aluminum is often used in cooking surfaces such as baking trays. Some stainless steel alloys are susceptible to acidity and salts.

9. Practicality

Aluminum is quite smooth, making it easy to cut, manipulate, mold, and extrude. In general, the use of aluminum is quite common, we can find it in soda cans, fans, doors, cars, among others.

On the other hand, steel is totally different, this is due to its great resistance to deterioration: it is more difficult to handle.

Summary of Steel vs Aluminium Comparison

As shown, there are many advantages and disadvantages when it comes to using aluminum and stainless steel. For the most part, aluminum will provide a lighter material, which can be a considerable advantage in certain applications, such as engine component details and car accessories. While steel is stronger, aluminum is lighter. 

The main advantage that stainless steel has over aluminum is its strength, also aluminum tends to be more expensive than stainless steel. In the end, both stainless steel and aluminum are versatile materials, and their advantages and disadvantages will depend on the application in which they are used.