Effect of tellurium on sulfide inclusion, microstructure and properties of industrial bars of a medium-carbon microalloyed steel

Tellurium is used for optimizing sulfide inclusion morphology in the iron and steel industry. In this study, the effects of tellurium on sulfide inclusion, microstructure, mechanical properties, fatigue performance, machinability, and corrosion resistance of industrial 38MnVS bars were investigated. The results show that the weight ratio of Te/S of the tellurium-treated steel was 0.043. Further, tellurium was mainly in the form of an MnS substitutional atom. The MnS inclusions were refined and strengthened via tellurium modification, promoting ferrite transformation and refinement. Additionally, the yield strength increased, and the elongation anisotropy decreased slightly after tellurium modification. However, the tellurium modification had an insignificant effect on the ultimate tensile strength. The ferrite refinement also promoted fatigue performance. Moreover, tellurium modification is beneficial for machinability. The cutting force was reduced, and the surface quality was improved after tellurium modification. Under the tellurium content conditions described herein, tellurium modification has an insignificant effect on corrosion resistance. The suggested tellurium content is below 0.075 times sulfur content for medium carbon microalloyed steels.