Linking Heat Treatment to Plastic Deformation in Pearlitic Steels Through Mesoscale Modeling

Rail and wheel steels undergo significant plastic deformation near the surface during service, contributing to wear and crack initiation. This region is exposed to a large deformation gradient, which affects the microstructure and local mechanical properties. This work models and predicts the plastic behavior of pearlitic steels based on microstructural features like phase fraction, interlamellar spacing, cementite thickness, and dislocation densities. A hypoeutectoid steel is heat‐treated to produce diverse microstructures, and the impact of proeutectoid ferrite, pearlite block size, interlamellar spacing, and cementite thickness on mechanical response is analyzed. Compression tests at room temperature and various strain rates, along with microscopy, characterize the samples. A mesoscale model is developed to describe plastic deformation at room temperature. Results show that lower austenitization temperature reduces grain and pearlite block size, while cooling rate inversely affects interlamellar spacing, cementite thickness, and proeutectoid ferrite. Tests indicate low strain rate sensitivity, with flow stress mainly controlled by cooling rate. Rapid cooling produces structures with strength over 1 GPa, while prior austenite grain size and block size have minimal effect on the strength of the pearlitic steel.