Modification of the composition and nonmetallic inclusions morphology as effective means of improving the quality of steel reduced with aluminium

A critical analysis is made of the problem concerning the effect of the residual concentration of aluminium on the character of inclusions in steel and on its properties, with reference being made to literature published abroad. The behavior of various types of sulfides during crystallization and deformation is shown. The basic requirements to regulation the composition and shape of non-metallic inclusions in steel are considered, including production of ultralowsulfur steel (up to 0.005% of sulfur), and a system with a limited sulfur content and introduction of potent oxide- and sulfide-formers. The most effective way of modifying inclusion is rational deoxidation with addition of rare-earth elements or calcium-containing alloys or compounds. Also shown is the effect of modifying on the mechanical properties