Selenium improves the machinability of steels. The “internal lubricant” properties of Selenium are retained in steels even when they are heat-treated up to at least 1300 Mpa (200 ksi). High alloy steel castings inoculated with 0.02% Se will show less pinhole and porosity even at hydrogen concentrations of 8 to 11 ppm. Selenium is used for improving the transverse ductility and toughness by adding equal proportion to the steel’s sulphur content. Selenium alters the shape of sulphide inclusions, making them more globular and is thus similar to Calcium and Rare earth metals. Higher concentration of Selenium - 0.05% to 0.10% significantly reduces the rate of nitrogen absorption in liquid steel and thus will have better cold forming properties.