Prediction of High-temperature Deformation Behavior of Low-carbon Bainitic Nb–Ti Micro-alloyed Steel Based on an Improved Strain–Stress Relation

• Published in: Transactions of the Indian Institute of Metals Vol. 72; no. 10; pp. 2793 - 2802
• Main Authors: Gao, Zhao-Hai, Cai, Qing-Wu, Xie, Bao-Sheng, Chen, Xu, Xu, Li-Xiong, Yun, Yang
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.10.2019; Springer Nature B.V
• Subjects: Alloying; Carbon; Chemistry and Materials Science; Computer simulation; Constitutive models; Corrosion and Coatings; Dynamic recrystallization; Errors; Heat treating; High strength low alloy steels; High temperature; Materials Science; Mathematical models; Metallic Materials; Microalloying; Model testing; Niobium; Predictions; Strain rate; Technical Paper; Thermal simulation; Tribology; Yield strength; Constitutive model; Hot compression; Low-carbon bainitic steel; Flow stress
• ISSN: 0972-2815; 0975-1645
• DOI: 10.1007/s12666-019-01756-3

Low-carbon bainitic Nb–Ti micro-alloyed steel was used in the present study to investigate the high-temperature deformation behavior. The high-temperature compression was carried out on a thermal simulation machine with a temperature range of 800 °C–1200 °C and a strain rate of 0.1–15 s −1 . Using work-hardening and softening mechanisms (dynamic recovery, dynamic recrystallization), a constitutive model was built on the basis of a newly proposed strain–stress relation, and flow stress at a strain rate of 0.5 and 10 s −1 was employed to test the established model. By means of comparing predicted and calculated results, the reliability of the model was proved, and the predictability of the flow stress model was also quantified in terms of root mean square error and average absolute relative error, which were calculated to be less than 11 MPa and 7.00%, respectively. These error estimators confirm the constitutive models based on the improved strain–stress relation and indicate an effective method to predict the high-temperature flow stress with high precision.