Effect of selenium on the structure and properties of structural steel

Small selenium additions (0.04–0.08%) have a substantial effect on the nature, morphology, and dispersity of nonmetallic inclusions and thus the mechanical, technological, and operating properties of structural steel.Selenium additions, leading to globularization of nonmetallic inclusions, reduce the anisotropy of the ductility and fracture toughness and also susceptibility to brittle fracture (tested with transverse samples).Microalloying with selenium reduces the loss of metal (scrap and rejects) due to metallurgical defects and also the tendency to form quench cracks.In terms of improved machinability with high-speed machining with use of hard-alloy cutters the addition of selenium is much superior to microalloying with lead, especially in machining with use of high-speed steels. Small selenium additions (0.04–0.08%) have a substantial effect on the nature, morphology, and dispersity of nonmetallic inclusions and thus the mechanical, technological, and operating properties of structural steel. Selenium additions, leading to globularization of nonmetallic inclusions, reduce the anisotropy of the ductility and fracture toughness and also susceptibility to brittle fracture (tested with transverse samples). Microalloying with selenium reduces the loss of metal (scrap and rejects) due to metallurgical defects and also the tendency to form quench cracks. In terms of improved machinability with high-speed machining with use of hard-alloy cutters the addition of selenium is much superior to microalloying with lead, especially in machining with use of high-speed steels.