How steel is tempered

 How steel is tempered

　　There are two main steelmaking processes commonly used in the world: blast furnace-blown oxygen furnace and electric arc furnace steelmaking, and there are also steelmaking methods that use a combination of the two steelmaking processes or other different processes.

　　The main difference in the process lies in the raw materials used. The main raw materials of blast furnace-blown oxygen furnace are iron ore, coke, and scrap steel, while electric arc furnace mainly relies on scrap steel and electricity for steelmaking. Other metallic iron raw materials such as direct reduced iron, molten iron can also be used for EAF steelmaking depending on plant setup and scrap steel availability.

　　BF-BOF steelmaking production accounted for 70.7%. First, iron ore is reduced to obtain iron, also called molten iron or pig iron, and then the molten iron is smelted into steel in an oxygen top-blown converter. After casting and rolling, the molten steel is processed into steel coils, steel plates, profiles or bars, etc. Deliverable finished product.

　　Electric arc furnace steelmaking uses electric arcs to melt scrap steel. Alloys are used as additives to adjust to the desired chemical composition, and electrical energy is supplemented by oxygen injection into the electric arc furnace. Downstream processes such as casting, reheating, and rolling are similar to the blast furnace-blown oxygen furnace process. About 28.9% of steel is produced by electric arc furnace.

　　Another steelmaking technology, the open-hearth steelmaking method, accounts for 0.4% of global steel production. This energy-intensive process is rarely used due to environmental and economic disadvantages.