Aluminum and stainless steel are two metals that are widely used in various industries. So, which one is the best? Well, that depends on many factors. Each metal is suitable for a specific application, and that makes it better in that field than the other. If you are trying to figure out which metal to use for your project, then you are in the right place. This article will help you differentiate between aluminum and stainless steel to find the ideal metal for you. Below is a breakdown of the two metals and explanations about which one is better for specific uses.

Stainless Steel

Aluminum vs. stainless steel

The chemical composition of stainless steel is mainly made up of iron, chromium, and nickel. Other alloying elements like manganese and copper are also present in its structure. At least 10.5% chromium is used in making stainless steel, and this addition makes it more resistant to corrosion. Additionally, stainless steel is non-porous and non-corrosive and also has a higher rust resistance.

The element that makes stainless steel less corrosive is the chromium oxide layer that forms on the surface when chromium reacts with atmospheric air.

This passive layer of chromium is often 12% to 13% and therefore too thin to be seen. However, it protects the metal beneath it. On the other hand, nickel helps in the process by restoring itself with oxygen, which makes the passive layer intact and unbroken. As long as this happens, the metal beneath it remains stainless.

However, stainless steel can still stain. If there is a scratch on the surface, it can lead to rust. Similarly, hot water that leaves deposits of chlorides can also cause some stains. But even though there is a possibility for staining, it is referred to as stainless steel because it does not rust or corrode as quickly as other ordinary steel.

Stainless steel: magnetism

Aluminum vs. stainless steel

Some stainless steel is magnetic while others are not. For instance, austenitic stainless steel is mostly not magnetic. On the other hand, ferritic stainless steel is conventionally magnetic because it has a higher concentration of iron. This means that magnets do not work on some types of stainless steel.

Aluminum

Aluminum vs. stainless steel

Aluminum has a higher resistance to corrosion because of passivation. Additionally, the metal has increased oxidation.  Aluminum is highly oxidized, and its surface turns white or pits, primarily if used in extremely acidic or basic conditions.

Aluminum is more robust and lightweight than most metals. Its strength increases significantly when blended with alloying elements. This property makes aluminum suitable for structural parts, heavy-gauge cookware, and housings for equipment.

Accordingly, aluminum conducts heat very well and has excellent thermal conductivity, which explains why it is preferred for use in cookware and general equipment that require perfect heat conductivity. In parallel, aluminum is more expensive compared to stainless steel.

Aluminum: magnetism

Aluminum vs. stainless steel

Aluminum is a metal, but it is essential to note that not all metals are magnetic, and aluminum is undoubtedly not. The extent of magnetism in metals depends significantly on the concentration of iron. That is why many types of steel are magnetic, and aluminum is not because it does not contain iron.

Aluminum vs stainless steel comparisons

Aluminum and stainless steel can be compared on many metrics. For instance, you have learned about aluminum vs stainless steel chemical composition. Other properties that can be used to make direct comparison include:

Aluminum vs stainless steel cost

The price of aluminum and stainless steel is a factor that should be considered when making a buying decision. It is essential to note that the cost of aluminum and stainless steel fluctuates depending on the demand and supply forces in the global market, the cost of fuel, and the availability of bauxite and iron ores, among others.

However, on a parallel scale, the price of stainless steel is significantly lower than the price of aluminum. The cost of raw materials considerably impacts the price of the two metals once spinning is completed. There may be exceptions based on different grades. However, two identical spinnings with one being aluminum and the other stainless steel, you will find that aluminum parts cost more because it requires more raw materials than stainless steel.

Aluminum vs stainless steel: corrosion resistance

Manufacturers prefer malleable materials at the production stage, and one of the most exceptional properties of aluminum is that it because highly resistant to corrosion immediately after it is spun and does not require further treatment processes. Aluminum does not need a coating or paint to prevent rust. On the other hand, stainless steel requires the chromium oxide layer on its surface and other treatment processes like the painting to avoid corrosion and rust. If the surface is scratched, there are chances of rusting. This requirement is even higher if the material is to be used in damp conditions.

Aluminum vs stainless steel: strength and malleability

Aluminum is more malleable and ductile than stainless steel. This makes aluminum an ideal choice for applications that require more forming to create various shapes and forms. On the other hand, stainless steel is robust and resilient. However, stainless steel cannot be formed to the same dimensional limits like aluminum because it cracks at some points due to its stiffness.

Aluminum vs stainless steel: weight difference

Even though stainless steel can corrode at some point, it is still harder than aluminum. Most spinnable tempers of aluminum dent quickly when under intense impact or pressure compared to stainless steel. Stainless steel, on the other hand, is more resilient, durable, and does not warp, deform, or bend easily under heat or pressure. However, this strength trades off with the weight, and therefore, stainless steel is much heavier and denser than aluminum. Typically, stainless steel is often 2.5 times heavier than aluminum.

The bottom line

The final application of materials depends on parts it is spun from and the balance between the pros and cons of the said material. On some spinning, the call can be a tough decision to make. However, when it comes down to aluminum vs stainless steel, you need to check the properties of each metal against the requirements of the project.