Manganese is used as an oxygenating element. This element produces sulfur with manganese sulfur (Mns), thereby reducing the inappropriate impact of iron sulfur and the brittle resulting from it. This element is of particular importance in steel and pig iron.
Adding a certain amount of ferromanganese to the alloy can reduce the risk of fracture of the components and dramatically reduce the critical cooling rate, thereby increasing the hardness of the product.
It also increases the strength of the product by adding some manganese. It is austenitic in steels with more than 12% manganese and with high carbon content, because manganese extends austenitic range substantially, steels produced by adding some ferromanganese resulting in shock stress to the outer surface, the hardness of their outer layer, is greatly enhanced by cold work while the inner part remains soft, which is why they are highly resistant to impacts and steels with more than 18% manganese High deformations are non-magnetic, and the alloys produced are special and are used as foam. Cold loads are used at very low temperatures and the thermal expansion coefficient of the steels is increased by adding some manganese while reducing their thermal and electrical conductivity.
Robert Hadfield discovered the benefits of high manganese steels, nowadays known as Hadfield steels, which have more specific uses such as iron rail and ore crushing equipment.
Manganese is generally one of the five main elements of ferro-alloys, which increases the tensile strength of 10kg / mm for every 3% of manganese, and if the manganese content is between 3% and 8%, the tensile strength increases with a lower proportion. Up to 8% manganese upward tensile strength decreases inversely, and yield stress variations are similar to tensile strength and also increase manganese hardness in pig iron.
In cases where they wish to increase the tensile strength, mechanical strength and toughness of alloy steels, they use high-carbon ferromanganese.