2.The melting point of steel is about 1500 degrees, and that of aluminum is 660 degrees. Aluminum impellers must not be used at high temperatures.
3. Steel is prone to oxidation in the air (such as galvanizing before
anti-corrosion treatment), while aluminum can form a dense oxide film
on the surface after oxidation,
making it impossible to continue oxidation. Aluminum impellers are
superior to steel impellers in slightly corrosive atmospheres.
4. The strength of steel is greater than that of aluminum. Due to strength limitations, the impellers of large fans are generally made of steel.