There are many aluminum alloy and stainless steel products in our life, such as pots, pans, doors and windows, and so on.
The biggest difference between them is that aluminum alloy is generally lighter in quality and dull in color, while stainless steel is heavier and brighter in color, in addition to their differences in price, hardness, performance, surface, use and so on. First is the strength, in short, stainless steel is much stronger than aluminum. Aluminum is less dense but stronger, closer to steel and more plastic; stainless steel is a nickel-chromium alloy that is harder than aluminum. However, this leads to their second difference: strength-to-weight ratio.
Strength-to-weight ratio. While aluminum is usually not as strong as stainless steel, it is almost one-third the weight of stainless steel, which is the main reason why aircraft are made of aluminum. Aluminum is also gaining popularity in the automotive industry to improve fuel.
Stainless steel has excellent corrosion resistance for two main reasons, firstly stainless steel has added chromium, which forms an invisible corrosion-resistant film around the steel. Secondly, it is non-porous, which increases corrosion resistance. On the other hand, aluminum has high oxidation and corrosion resistance, mainly due to its passivation layer. When aluminum is oxidized, its surface becomes white and sometimes pitted, due to the small holes formed by corrosion on the surface, and in certain extremely acidic or alkaline environments, aluminum can corrode rapidly with catastrophic results.
Electrical conductivity, compared to most metals, stainless steel is a very poor conductor. Aluminum is a very good conductor of electricity. Because of its high electrical conductivity, lightweight and corrosion resistance, high-voltage overhead power lines are often made of aluminum, and some older houses even use aluminum wire instead of copper.
Thermal conductivity, aluminum products have better thermal conductivity than stainless steel products, which is one of the main reasons why aluminum is used in automotive radiators and air conditioning units.
Stainless steel can be used at much higher temperatures than aluminum, depending on the application, stainless steel can be used above 800 degrees, and aluminum can become very soft above about 400 degrees.
Workability, aluminum is quite soft and easy to cut and form. Stainless steel is difficult to use due to abrasion and wear resistance, stainless steel is harder than aluminum and more difficult to form.
Welding, stainless steel is relatively easier to weld, while aluminum is quite difficult.
The impact on food, stainless steel is less reactive with food, and aluminum can produce reactions that affect the color and taste of food.
Cost, usually aluminum is cheaper than stainless steel, which may be the deciding factor in which metal you choose for your next project.