Effect of antimony on low-temperature tensile deformation behaviour of high-grade non-oriented silicon steel

The effects of antimony (Sb) on the deformation behaviour of high-grade non-oriented silicon steel at a low temperature were studied by using a Gleeble-3800 thermal simulator and the field-emission scanning-electron microscope. The tensile strength of the high-grade non-oriented silicon steel without Sb was significantly lower than that of the high-grade non-oriented silicon steel with Sb within the tensile temperature range of 25 °C–240 °C. It is possible for Sb atoms near the grain boundary to diffuse at hundreds of atoms through dislocations as a rapid diffusion channel, which is driven by thermal activation with an increase in temperature. Atomic diffusion can weaken the damage to bonding forces on the grain boundary and crack propagation along the grain boundary under load action. The segregation of Sb atoms at the grain boundary decreased gradually, which weakened the cleavage characteristics of the fracture morphology and enhanced its dimple characteristics. For a stretching temperature of 80 °C, the fracture dimple of high-grade non-oriented silicon steel without Sb was significantly more than the high-grade non-oriented silicon steel with Sb. Because of the weakening effect of Sb segregation at the grain boundary, the suitable low-temperature deformation range for high-grade non-oriented silicon steel with Sb was 120 °C–160 °C.