High-temperature tensile behavior and constitutive model comparison for 20MnTiB steel

Purpose Due to its high strength and low-alloy composition, 20MnTiB cold-heading steel is widely used in critical structural applications across sectors such as aerospace, marine engineering and nuclear power. This study systematically investigates the high-temperature tensile behavior and constitutive modeling of 20MnTiB cold-heading steel. Design/methodology/approach Isothermal tensile tests were conducted under various deformation conditions (temperatures from 1173 K to 1373 K and strain rates from 0.1 to 10 s−1) to evaluate the material’s flow characteristics and fracture mechanisms. Microstructural analyses using optical and scanning electron microscopy revealed that high-temperature plastic deformation is primarily governed by dynamic recovery and work hardening, with localized necking and microvoid coalescence leading to ductile fracture. A strain-compensated Arrhenius-type constitutive model and a modified Johnson−Cook model were developed to accurately describe the material’s thermal deformation behavior. Findings Comparative evaluation of the models demonstrated that the Arrhenius model achieved a correlation coefficient of R² = 0.995 and AARE = 2.99%, outperforming the modified Johnson−Cook model, which yielded R² = 0.983 and AARE = 5.49%. These results confirm that the strain-compensated Arrhenius model provides a more accurate and reliable prediction of the high-temperature tensile flow behavior of 20MnTiB steel. Originality/value In this study, isothermal tensile tests were performed under various deformation conditions to systematically examine the material’s high-temperature tensile response. The underlying deformation mechanisms and fracture characteristics were thoroughly analyzed. These models’ accuracy and predictive capabilities were validated through experimental data, demonstrating their potential for practical application.