NONMETALLIC INCLUSIONS IN AUSTENITIC STAINLESS STEEL AISI 303 MICROALLOYED WITH ZIRCONIUM AND TELLURIUM

The control of formation of nonmetallic inclusion and the characterization present the basis of improvement of steel product properties and lead to sustainable development in design of new steel grades. In order to produce steels with better machinability, such as AISI 303 grades, a modification of inclusions with carefully designed chemical composition is presented. Sulphur by creating sulphide inclusions reduces friction and cutting resistance, and increases the brittleness of the chip.Considering its harmful effect in steel, as well as the fact that non-metallic inclusions have been insufficiently tested for this type of high-alloyed steel, the aim of this research is to determine effects of microalloying on the possibility of modification of non-metallic inclusions. Modification with zirconium favorably affects the ductile properties of steel, and a step forward in this study is a modification of inclusions with tellurium.It is of particular importance to determine the behavior of non-metallic inclusions in the process of production of the structural part and in subsequent exploitation. Therefore, plastic processing of austenitic stainless steel was also carried out, forging and rolling with two different level of processing.