Effect of Sulfur on Antimony-Induced High-Temperature Ductility Deterioration of C-Mn Steel

The recycling of steel scrap is becoming more and more developed to save resources and protect the environment. However, impurities such as antimony in steel scrap cannot be economically and effectively removed, resulting in an inevitable accumulation of impurities. Once the impurity concentration exceeds a certain limit, they will have a great impact on the ductility deterioration and hot shortness of steel. It has been shown that sulfide can inhibit the precipitation of residual elements, such as copper at grain boundaries, in steel. The effect of sulfur on the thermoplasticity of antimony-containing C-Mn steel at 700–1100 °C was examined using a Gleeble 1500 thermodynamic simulation device (Gleeble, Poestenkill, NY, USA). Area reduction (RA%) was used to evaluate the thermal ductility. The 0.16 mass % Sb extended the range of the ductile grooves, reducing the RA% at 750–950 °C. Antimony (Sb) was found to segregate at the boundaries tested by an electron probe microanalyzer. Additionally, scanning electron microscopy was used to examine the fracture morphology, which exhibited the characteristics of intergranular failure. In contrast, the addition of sulfur to the steel compensated for the deterioration of the thermal ductility caused by the Sb