The difference between pure iron, steel and pig iron mainly lies in the difference in carbon content.
If the carbon content is more than 0.02%, it will become a low-carbon steel with low hardness that can be used to pull iron wires, roll thin white iron plates, etc. If the steel with a carbon content of 0.25% to 0.6% is called medium carbon steel, its hardness is medium, and it can be rolled into construction steel, steel plates, nails and other products.
If the carbon content is 0.6% to 2.0%, it will become a high-hardness, high-carbon steel that can be used for making knives, dies, etc.
The combination of low, medium and high carbon steels is called “carbon steel”.
If the carbon content exceeds 2.0%, it will become a hard and brittle cast iron pot, radiator, plow and other pig iron. The general pig iron carbon content is 3.5%-5.5%.
Therefore, industrial pure iron is a kind of steel. Its chemical composition is mainly iron, with a content of 99.50%-99.90% and a carbon content of 0.04% or less.
Because it is not actually pure iron, this kind of steel close to pure iron is called industrial pure iron.