Steel and aluminium are common metals and are produced and exist in large quantities. Both steel and aluminium can conduct heat depend on the number of free electrons present in the element. So there's a rule saying that the thermal conductivity (at some temperature) is proportional to the electrical conductivity Both of the materials can withstand and bear extreme pressure and tons of load. The tensile strength of high-grade aluminium is in same ratio as high-grade steel.
Aluminium beats steel, as its bending density is about 1/3 of the density of steel, and the advantage of thickness offsets the 1/3 in strength, making aluminum more dent resistant than steel of the same weight. One difference that steel has compared to aluminum, is that after repeated loads, aluminum will fatigue. Steel has an indefinite fatigue life, which means it has enough strength to withstand repeated load cycles, and hence, it is durable.
Steel is heavier than aluminium, as steel is about three times heavier for the same length of aluminium. Aluminum is non-magnetic compared to steel, however, some types of steel alloys are also non- magnetic. If we make this comparison on the basis of the micro-structure of the steel and aluminum, we find that the carbon iron component of iron structures are not magnetic at all. Aluminium are generally much more expensive than steel, because of the materials they are made from and the more involved manufacturing process.
An advantage that steel has over aluminum is its surface hardness, which is much harder than aluminium. Aluminum's Formability is approximately 2/3 that of steel (less forming range). This is a very important advantage for steel for vehicle styling and overall manufacturing robustness. Unlike steel, aluminum won't corrode when exposed to harsh weather condition such as salty environment. Due to factors including its corrosion resistance and smooth, shiny appearance, aluminum stays good looking longer than steel.