Prospect of Tellurium in High-Temperature Carburizing Gear Steels: An Industrial Study

This work is a continuation of our previous research. We successfully produce low-carbon gear steel containing trace tellurium (Te) through industrial production line (EAF-LF-VD-CC), and we investigate the effects of a trace Te addition on the precipitation of MnS inclusions in sulfur-containing gear steel billets, the machinability of rods, and the high-temperature vacuum carburizing performance of rods. This study demonstrates that the addition of trace Te in steel can be achieved in industrial production without causing disruptions in the steelmaking process. The Te addition effectively induces spheroidization and refinement of MnS inclusions in industrial cast billets, showing good consistency with laboratory Te alloying experimental results. Furthermore, the Te addition reduces the deformation rate of MnS inclusions during industrial rolling processes. Benefiting from the spheroidization of MnS inclusions, the chip-breaking performance during the machining of Te-containing rods is significantly optimized, along with substantial improvement in machined surface roughness. The industrial rods exhibit excellent grain stability during 960 °C high-temperature vacuum carburizing, with carburizing rates significantly enhanced compared to conventional gear steels. This work comprehensively demonstrates the multifaceted effects of Te treatment on gear steel properties, particularly providing valuable references for developing high-temperature carburizing gear steels.