Manganese has a wide range of uses, involving all aspects of human production and life. About 90% of the manganese produced in the world is used in the iron and steel industry, and the other 10% is used in non-ferrous metallurgy, chemical industry, electronics, batteries, agriculture and other industries.
Manganese is a beneficial element in steel. The main functions of manganese in steelmaking are deoxidation, desulfurization and as an alloying element.
In the process of steelmaking, some iron will be oxidized together with impurity elements to form ferrous oxide. Due to the high solubility of ferrous oxide in molten steel, the oxygen content in molten steel will increase, and the increase in oxygen content in molten steel will increase the oxygen content in molten steel. It affects the performance of the steel, so the oxygen content of the steel is strictly required not to exceed 0.02% during the production process. When manganese is added to molten steel, manganese will react with ferrous oxide to form oxide slag that is insoluble in molten steel, and the formed oxide slag will float on the liquid surface of molten steel, thereby achieving the purpose of reducing the oxygen content in steel. In addition, manganese can also reduce FeO in steel to iron to better improve the quality of steel.
In molten steel, sulfur exists in the form of iron sulfide. During hot working of steel, the premature melting of FeS compounds can lead to cracking of the workpiece, resulting in hot embrittlement, reducing the ductility and toughness of the steel, and causing cracks during forging and rolling. Sulfur is also detrimental to weldability, reducing corrosion resistance. The binding force of manganese and sulfur is stronger than that of iron and sulfur. Therefore, after adding manganese alloy to molten steel, manganese sulfide with high melting point will be formed and then transferred to slag, which will reduce the sulfur content in steel and improve the Forgeability and Rollability.
Manganese can improve the wear resistance, hardenability, strength and hardness of steel, so it can become an important alloying element of various steels. For example, if 0.8%-1.7% manganese is added to low-alloy steel, the strength of the steel can be increased by 20%-30% compared to ordinary carbon steel.