Abstract: High temperature unidirectional hot compression test of a new type low carbon and high alloy bearing steel was carried out by means of Gleeble-3500 thermal simulation machine under the conditions of deformation temperature of 900-1200 ℃, strain rate of 0.01-1 s^-1 and total deformation of 50%. The effect of the deformation temperature and strain rate on the mechanical behavior of the tested steel during hot deformation was analyzed through flow stress curves at high temperatures under different conditions. The Arrhenius equation was used as a constitutive model to develop the high-temperature constitutive equations for the tested steel, and the hot processing maps for the 50% deformation were drawn based on the Mutry instability criterion. The results show that the dynamic recovery characteristics of flow stress curves are obtained at low temperatures and small strain rates (900-1000 ℃, 0.01-0.05 s^-1), and dynamic recrystallization occurs at high temperatures and low strain rates (1050-1200 ℃, 0.01-0.1 s^-1) during deformation. At higher strain rate (1 s^-1), the flow stress increases with increasing strain, and the curves show no significant peak stress. At medium and high temperatures and low strain rates (1050-1200 ℃, 0.01-0.1 s^-1), the uniform fully dynamic recrystallized structure can be obtained, and the hot working performance of the material is the best.

Key words: heat resistant bearing steel, hot deformation behavior, constitutive equation, hot processing map