ABSTRACT
In the manufacture of steel coils, the raw material iron ore is fed into a blast furnace, together with limestone and coke; the coke is used as a source of heat, while the limestone acts as a flux and separates impurities from the ore. The ore is quickly reduced to molten iron, known as pig iron, which contains approximately 3-4 per cent carbon. In the next stage of manufacture, the iron is changed into steel by reheating it in a steel-making furnace and blowing oxygen either into the surface of the iron or through the liquid iron, which causes oxidation of the molten metal. This process burns out impurities and reduces the carbon content from 4 per cent to between 0.08 and 0.20 per cent.
