Carbon, Alloy, Stainless, and Tool are the four steel categories. Carbon steels contain simply carbon and iron. This set of four steel grades accounts for 90% of steel manufacturing. Adding nickel, copper, chromium, and aluminium creates alloy steels. These components improve steel's strength, machinability, flexibility, and corrosion resistance. Stainless steels are alloyed with 10-20% chromium, nickel, silicon, manganese, and carbon. These steels have strong corrosion resistance and can tolerate adverse weather, making them safe for outdoor construction. Tool steels are used for cutting and drilling. Tungsten, molybdenum, cobalt, and vanadium provide heat resistance and durability.