Modeling of Carbide Spheroidization Mechanism of 52100 Bearing Steel Under Warm Forming Conditions

Abstract

Direct deformation spheroidization of bearing steel can produce a fine and homogeneous microstructure. Warm-compression experiments were performed to investigate the carbide spheroidization behavior of 52100 bearing steel at temperatures of 650 °C to 750 °C and strain rates of 0.1 to 10.0 s−1. A set of mechanism-based unified constitutive equations was developed using the internal state variable method to describe the carbide spheroidization and metal flow behaviors of 52100 steel under warm deformation. The carbide spheroidization fraction, dislocation density, and phase transformation were modeled and correlated with unified constitutive equations. Material parameters in the constitutive equations were determined using genetic algorithm optimization techniques. The developed constitutive equations were validated by comparing the predicted and experimental results. Good consistency between these results indicated that the carbide spheroidization and metal flow behavior could be predicted using these constitutive equations.