1. Manganese (Mn)
In the process of steelmaking, manganese is a good deoxidizer and desulfurizer. Generally, steel contains 0.30-0.50% manganese. When more than 0.70% of carbon steel is added, it is called "manganese steel". Compared with ordinary steel, it has not only enough toughness, but also higher strength and hardness. It can improve the hardenability of steel and improve the hot workability of steel. For example, the yield point of 16Mn steel is 40% higher than A3 steel. The steel containing 11-14% manganese has extremely high wear resistance, which is used for excavator bucket, ball mill liner, etc. The increase of manganese content weakens the corrosion resistance of the steel and reduces the welding performance.
2. Sulfur (S)
Sulfur is also a harmful element under normal circumstances. It makes the steel produce hot brittleness, reduces the ductility and toughness of the steel, and causes cracks during forging and rolling. Sulfur is also bad for welding performance, reducing corrosion resistance. Therefore, the sulfur content is generally required to be less than 0.055%, and the high quality steel is required to be less than 0.040%. Adding 0.08-0.20% sulfur to steel can improve machinability, which is usually called free cutting steel.
