Differences Between Stainless Steel and Aluminum

- Dec 06, 2016 -

As we all know that stainless steel and aluminum might look similar, but they are actually quite different. The following lists their differences and keep in mind when you deciding which type of metal to use in your next project.

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Stainless Steel Pipe Tube
Stainless Steel Sheet Coil
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Stainless Steel Bar
Stainless Steel Pipe Fitting

Strength to weight ratio. Aluminum is typically not as strong as steel, but it is also almost one third of the weight. This is the main reason why aircraft are made from Aluminum.

Corrosion. Stainless steel is made up of iron, chromium, nickel, manganese and copper.  The chromium is added as an agent to provide corrosion resistance.  Also, because it is non-porous the resistance to corrosion is increased. Aluminum has a high oxidation and corrosion resistance mainly due to its passivation layer.  When aluminum is oxidized, its surface will turn white and will sometimes pit. In some extreme acidic or base environments, Aluminum may corrode rapidly with catastrophic results.

Thermal Conductivity. Aluminum has a much better thermal conductivity (conductor of heat) than stainless steel. One of the main reasons it is used for car radiators and air conditioning units.

Cost. Aluminum is typically cheaper than stainless steel.

Workability. Aluminum is fairly soft and easier to cut and form. Due to its resistance to wear and abrasion, Stainless can be difficult to work with. Stainless steels are harder and are especially harder to form than aluminum.

Welding. Stainless is relatively easy to weld, while Aluminum can be difficult.

Thermal properties. Stainless can be used at much higher temperatures than Aluminum which can become very soft above about 400 degrees.

Electrical Conductivity. Stainless steel is a really poor conductor compared to most metals. Aluminum is a very good conductor of electricity. Due to its high conductance, light weight, and corrosion resistance, high-voltage overhead power lines are generally made of aluminum.

Strength. Stainless steel is stronger than Aluminum (provided weight is not a consideration).

Effect on Foods. Stainless steel is less reactive with foods.  Aluminum can react to foods which may affect color and flavor.

Toxicity. When aluminum enters the body (say, through aluminum cookware that touches your food), it continues to build up in the body's tissues, and is very hard to remove via chelation therapy, especially from the bones and brain.