Study on hot tensile deformation and fractography of 410 martensitic stainless steel produced by radial forging process

The aim of the current research was to investigate the hot tensile behavior and fracture morphology of 410 steel in the temperature range of 950-1100°C and two strain rates of 0.05 s-1 and 0.5 s-1. The results showed that the peak stress and yield stress decreased with increasing temperature, which confirmed the decrease of strength against deformation with increasing process temperature. In strain rate of 0.05 s-1 with increasing temperature, the peak strain decreased continuously, while in strain rate of 0.5 s-1 was observed an increment trend after initial decrease due to competition between work hardening and softening mechanism such as dynamic recovery and dynamic recrystallization. The fracture morphology results showed that they were in good agreement with the mechanical results when at 950 °C the brittle fracture mechanism had a high contribution and the soft fracture surface morphology (increasing dimples and decreasing cleavage planes) was dominant with increasing process temperature. At strain rate of 0.05 s-1, the size of the voids and cracks formed during process was much larger than the cracks created at strain rate of 0.5 s-1, which indicated considerable tearing and decrease in fracture strain (elongation) of the samples in during hot tensile testing at low strain rate.