Ferroalloys are a category of alloyed iron that contains a large number of other elements including manganese (Mn), aluminium (Al) and silicon (Si). Because of their brittle and unusable structure, ferroalloys are not a stand-alone option for industrial applications. However, when combined with alloyed steels, these metals exhibit unique and advantageous properties. In addition, ferroalloys have lower melting points than pure elements and are added to liquid steel to create desired properties for specific products.
Ferroalloys are a vital component in the steel and alloy industries, giving steel and cast iron distinctive characteristics and performing critical functions throughout the process. The main applications are as follows:
Ferroalloys act as oxygen absorbers during the steel making process. During the oxidation of steel, unwanted impurities in the iron are removed by oxygen, forming slag. The presence of residual oxygen in the iron leads to the formation of holes, which negatively affects the quality and mechanical properties of the material. To prevent quality degradation, it is necessary to deoxygenate the material. This can be achieved by adding elements that have a higher affinity for oxygen than iron, such as chromium (Cr), aluminium (Al), silicon (Si) and manganese (Mn). Alloys such as ferromanganese, ferrosilicon, silicon-chromium, silicon-calcium and aluminium-silicon are used for deoxygenation.
Ferroalloys are added in the process to modify the properties of the steel. Ferrochrome, medium to low carbon ferromanganese and ferrovanadium are alloying additives that improve the properties of the final product by changing the phase transition line in the steel. Chromium, for example, improves the structural quality, stability and rust resistance of steel, while manganese improves the strength and stability of gamma phase steel.