IMnI - Manganese and Steelmaking Industrial and Metallurgical Applications Manganese and Steelmaking Steel is basically an alloy of iron and carbon, consisting of an iron phase and iron carbides.
Crude steel produced from iron contains an undesirable amount of oxygen and some sulphur.
Desulphurisation processes reduce the need for manganese in this respect. These alloying uses depend on the properties of steel. Steel, as has been noted, contains iron and carbon. When the steel is cooled down slowly, the carbon, soluble in austenite, precipitates as an iron carbide called cementite, the austenite transforms to ferrite and they precipitate together in a characteristic lamellar structure known as pearlite. Manganese plays an important role as it lowers the temperature at which austenite transforms into ferrite, thus avoiding cementite precipitation at ferrite grain boundaries, and by refining the resulting pearlitic structures.