Silicomanganese is a rocky material with a silvery, metallic appearance. Both silicon and manganese contribute considerably to the properties of steel, depending on the amount added and their combined effect with other alloying elements. Silicon and manganese both react strongly with oxygen and act as deoxidizers.
The use of silicomanganese has the effect of adding less carbon to the steel compared to an equivalent basket of standard ferrosilicon 75 (FeSi 75) and high-carbon ferromanganese (HCFeMn). Computational fluid dynamics calculations show that the silicon yield of silicomanganese is higher than that of standard FeSi 75.
Low-carbon silicomanganese (LCSiMn) occurs as a rock with a silvery, metallic appearance. It is mainly used in stainless steel production as part of AOD (Argon Oxygen Decarburization), VOD (Vacuum Oxygen Decarburization).
During decarburization, the use of low-carbon silicomanganese instead of high-carbon ferromanganese results in productivity improvements of 4-6%. It also reduces the amount of oxidized manganese, and therefore the amount of silicon required. Eventually, it improves life span of the furnace lining due to the use of a less fluid slag (less manganese oxide (MnO)).
It can also replace both manganese metal and ferrosilicon in the production of certain grades of low-carbon steel. The amount of phosphorus input is significantly reduced because the Mn/P ratio is considerably higher in low-carbon silicomanganese than in high-carbon ferromanganese.
High-carbon ferromanganese is a lumpy material with a metallic appearance, which becomes covered in a dark layer of oxides during storage. When added to steel, manganese has a significant influence on the structure and properties of the steel, improves tensile strength, workability, toughness, hardness and abrasion resistance. It also reacts with the remaining sulfur in the steel, preventing surface cracking.
Medium- and low-carbon ferromanganese
Medium- and low-carbon ferromanganese is a lumpy material with a silvery, metallic appearance. By adding manganese in the form of MC/LCFeMn instead of HCFeMn, approximately 80% to 93% less carbon needs to be added to the steel (for a steel containing 2% manganese). Since the alloy is delivered in lump form, it provides a higher manganese yield compared to electrolytic manganese delivered in flakes.