<p>The effects of different deformation conditions on the actual stress-strain curve, mechanical properties, microstructure evolution, and fracture behavior of as-cast 50Cr5NiMoV steel were systematically studied by thermal tensile experiments at different temperatures (900–1200°C) and strain rates (0.001–1&#xa0;s⁻¹). The Bonora fracture damage model was established to predict the occurrence of fracture. The results show that the actual stress-strain curve is divided into four stages. With the increase in temperature and the decrease in strain rate, the flow, yield, and peak stress decrease gradually, but the changing trend of fracture strain and elongation is the opposite. The recrystallization mechanism of as-cast 50Cr5NiMoV steel is mainly discontinuous dynamic recrystallization, and the increase in temperature is conducive to the increase of dynamic recrystallization volume fraction and microstructure uniformity. With the increase in temperature and the decrease in strain rate, the fracture morphology changes gradually from small and shallow dimples to large and deep dimples. At the same time, the Bonora model is established to predict fracture failure. The established fracture damage model correlates well with the experimental results, and the maximum relative error is only 10.3%.</p>