Insights into deformation-induced heating: Temperature-strain prediction in SCM440 steel under deformation scenarios.

Recently, deformation-induced temperature was found to be predictable based on corresponding strain, enabling broader applications in temperature prediction and strain measurement. This prediction relies on the temperature-strain relationship during deformation. However, the influence of deformation rate has not been addressed, despite most materials exhibiting rate-dependent behavior that affects both material properties and deformation-induced temperature. This study aims to explore the rate-dependent behavior of the temperature-strain relationship and develop a prediction model. Thermal-strain analysis reveals a linear correlation between deformation-induced temperature and plastic strain, with rate-dependent behavior governed by the deformation rate. Relationships among change in temperature difference per unit strain, heat generation rate, and strain rate are utilized to establish the prediction model. The developed model is primarily applied under various deformation conditions in uniaxial tensile testing. Prediction results for temperature and strain closely match measured values, with an overall difference within 5 % in most cases, except at slow deformation rates where strain estimation is less effective due to dominant heat convection. The model was also applied to three-point bending tests with different artificial-defect specimens, revealing predictable temperature results with a maximum difference of 7 % and estimated strains agreeing with a 5 % error band in the initial 20 % of plastic strain development. Both findings underscore the crucial influence of heat transfer on prediction accuracy, suggesting its necessity in further improvements. This study provides insights into temperature-strain prediction driven by deformation-induced heating, offering guidance for temperature-strain prediction methods and paving the way for applications in thermal-based inspection and temperature-based strain measurement.