Tailoring Sulfide Morphology in 36MnVS4 Nonquenched and Tempered Steel with Trace Te–Ce Treatment

Achieving superior sulfide morphology control is essential for advancing nonquenched and tempered steel into high‐end markets. Although tellurium (Te) addition offers exceptional modification efficacy, its high cost presents a major economic barrier. The rare‐earth element cerium (Ce) is relatively low‐cost and also demonstrates a moderate efficacy in sulfide modification. This study, therefore, investigates the effects of trace Te and Ce additions on sulfide modification in 36MnVS4 nonquenched and tempered steel. Systematic characterization reveals that Te + Ce composite modification transforms the inclusions, replacing MnS–Al 2 O 3 with MnS–CeAlO 3 , and forming Ce 2 (S, Te) 3 –MnS, MnTe–MnS, and Ti 4 C 2 S 2 . It also effectively alters MnS morphology from clustered to chain‐like and sphere‐like, improving its distribution without significantly changing its size or area fraction. The added Ce promotes microstructural homogenization by forming fine AlCeO 3 inclusions that acted as nucleation sites for intragranular ferrite. Furthermore, Te increases sulfide hardness, enhancing their deformation resistance during hot compression, as confirmed by stress–strain curves where Te is identified as the primary element improving hot ductility. Consequently, the optimal trace addition of 17 ppm Te and 9 ppm Ce successfully reduces the average inclusion aspect ratio at 1050 °C from 3.3 to 3.0, demonstrating an effective strategy for sulfide control.