They are both malleable - they can be bent or pressed into shape. The table summarises some differences in their properties. Aluminium has some advantages over steel.
Since it has a lower density than iron or steel, a car body made from aluminium will be lighter than the same car body made from steel. This results in improved fuel economy. Also, aluminium does not corrode easily because it has a protective layer of aluminium oxide. Therefore, a car body made from aluminium will corrode less than one made from steel. The ions separate, and the residual liquid cools and becomes aluminum.
Steel is flexible, strong, and durable. Steel is a mixture of the elements iron and carbon. Iron is mined, smelted the impurities are removed, carbon is added, and the result is carbon steel. This is the base for other types of steel, such as stainless and chrome-moly. Steel is stronger compared to aluminum. The amount of carbon in steel makes it heavier and unyielding. The higher amount of carbon in an alloy, the harder it becomes.
Aluminum is used for transportation, packaging, construction, utensils, electric transmission lines, paint, etc. Steel is used for roads, railways, other infrastructure, appliances, buildings, transportation, aerospace, etc. Heavier compared to aluminum. Carbon steel is heavy. Aluminum is less corrosive.
There is no paint or coating to wear or scratch off. It has a high oxidation and corrosion resistance. When aluminum is oxidized, its surface will turn white and will sometimes pit.
Steel is highly corrosive and usually needs paint or treatment to protect it from rust and corrosion especially if it will be in a moist, damp or abrasive environment. Cost is always an essential factor to consider when making and using any product. Some steels are coated with other materials "galvanized" to reduce the rate of corrosion. So if you want to observe rusting sooner, don't pick one of these metals.
Go and get some raw iron unpainted, no oils or other coatings , and leave it in a moist environment with air flow. Most chemical reactions take place faster when the temperature's higher, so it cannot hurt to keep it in a warm place.
The exposed surface area of the metal helps enormously -- each bit of surface should rust at the same rate. If you have a solid lump of iron, only the outside will rust.
Something that should rust very very quickly is a piece of ungalvanized steel wool some scouring pads are actually made of stainless steel!
Don't use one of these which is kept wet. Aluminum forms an oxide coating very quickly too, but it is very thin and tough, and prevents further oxidation of the underlying aluminum. Other ways to speed corrosion -- adding salt to the water may help. Joining dissimilar metals in something which contacts saltwater may be an invitation for corrosion.
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