Constitutive investigation based on the time-hardening model for AH36 material in continuous casting process

A detailed understanding of the constitutive behavior of AH36 material in continuous casting process was obtained through various high-temperature tensile testing at specific ranges of temperatures (1173-1673 K) and strain rates (10(-4)-10(-2) s(-1)) using a Gleeble system. A significant variation in flow stress is evident over the entire range of temperatures under different strain rates. The constitutive equation of the AH36 material was suggested based on the time-hardening model. The results indicate that the accuracy of the model is relatively low at the temperatures of 1173, 1573, and 1673 K under the strain rates of 10(-2) and 10(-4) s(-1). Therefore, a modification of the time-hardening model was carried out by including the compensation of strain rate in the Zener-Holloman parameter (Z) to improve the accuracy. Furthermore, the deformation process was distributed into the regions of 1173, 1273-1473, and 1573-1673 K based on the exponent of strain rate at different ranges of temperature. The correlation coefficient between the computed and experimental flow stress data is 0.998. The average absolute relative error is within the range of allowable experimental conditions.