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Aluminum and Stainless Steel might look similar, but they are actually quite different. Keep these 10 differences in mind when deciding which type of metal to use in your next project:aluminum vs. stainless

        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.

Steel and aluminum are the two most popular materials used in both metal spinning and metal stamping. Each material has a defined and distinct set of characteristics that make it the right – or the wrong – material for the job. When selecting material for your spun part it’s important to consider the following: cost, the shape of the spinning, and most importantly the end application.

Aluminum vs Steel Cost
Cost and price are always an essential factor to consider when making any product. The price of steel and aluminum is continually fluctuating based on global supply and demand, fuel costs and the price and availability of iron and bauxite ore; however steel is generally cheaper (per pound) than aluminum (see galvanized vs stainless for more info on steel). The cost of raw materials has a direct impact on the price of the finished spinning. There are exceptions, but two identical spinnings (one in aluminum and one in steel) the aluminum part will almost always cost more because of the increase in the raw material price.

Strength & Malleability of Steel vs Aluminum
Aluminum is a very desirable metal because it is more malleable and elastic than steel. Aluminum can go places and create shapes that steel cannot, often forming deeper or more intricate spinnings. Especially for parts with deep and straight walls, aluminum is the material of choice. Steel is a very tough and resilient metal but cannot generally be pushed to the same extreme dimensional limits as aluminum without cracking or ripping during the spinning process.

Corrosion Resistance of Steel and Aluminum
While malleability is very important for manufacturing, aluminum’s greatest attribute is that it is corrosion resistant without any further treatment after it is spun. Aluminum doesn’t rust. With aluminum there is no paint or coating to wear or scratch off. Steel or “carbon steel” in the metals world (as opposed to stainless steel) usually needs painted or treated after spinning to protect it from rust and corrosion, especially if the steel part will be at work in a moist, damp or abrasive environment.

Weight Differences in Steel and Aluminum
Even with the possibility of corrosion, steel is harder than aluminum. Most spinnable tempers and alloys of aluminum dent, ding or scratch more easily as compared to steel. Steel is strong and less likely to warp, deform or bend under weight, force or heat. Nevertheless the strength of steel’s tradeoff is that steel is much heavier /much denser than aluminum. Steel is typically 2.5 times denser than aluminum.

The final application of the part will ultimately determine which material the part would be spun from, balancing all the limitations and advantages of each material. On some spinnings it’s an easy call, while others are a tougher decision. If you or your engineering departments are on the fence with a steel vs. aluminum dilemma, please contact the authority on metal spinnings at Wenzel Metal Spinning, Inc. and we will be happy to provide you with our expert opinion and supporting information. Additional information about steel and aluminum can be found on our materials page.

Aluminum has a much lower density than stainless steel, so materials made from it can be lighter in weight. On the other hand, aluminum is much more subject to corrosion than stainless steel, so outside exposure will lead to deterioration much more quickly than stainless.