HOT-COMPRESSION DEFORMATION BEHAVIOR AND CONSTITUTIVE EQUATIONS OF LZ50 AXLE STEEL
Abstract
A study of deformation behavior of LZ50 axle steel has great significance to the railway industry. Hot-deformation tests were performed using a Gleeble-3800 thermal mechanical simulator at temperatures of (900, 1000 and 1100) °C with strain rates of (0.1, 1.0 and 10.0) s–1 under different deformation degrees of 0.2, 0.6 and 1.0. True stress-strain curves were discussed to obtain hot-processing maps. Then hot-processing maps of LZ50 steel at different deformation parameters were discussed including safe zones and unsafe zones. Finally, thermal deformation constitutive equations and dynamic recrystallization models were established based on the experimental data. The results show that at a strain rate of 10.0 s–1, the peak value of the flow stress increases by approximately 40 MPa with a decrease in the temperature from 1000 °C 900 °C, which is larger than the value of 18 MPa obtained at a decrease from 1100 °C to 1000 °C. At deformation temperatures of 900–1000 °C, the peak value of the flow stress increases by approximately 37 MPa with the strain rate increasing from 0.1 s–1 to 1.0 s–1, while from 1.0 s–1 to 10.0 s–1, the increase is approximately 21 MPa. With an increase in the strain from 0.2 to 1.0, the instability area under the low deformation temperature expands due to a higher strain rate. The activation energy of dynamic recrystallization is 334.537 kJ/mol.
References
2. J. Lin, Y. Liu, D.C.J. Farrugia, M. Zhou, Development of dislocation-based unified material model for simulating microstructure evolution in multipass hot rolling. Philos. Mag. 85(18), 1967-1987 (2005)
3. D. Shiwen, C. Shuangmei, Hot deformation behavior and processing maps of LZ50 steel. TRANSACTIONS OF MATERIALS AND HEAT TREATMENT 37(03), 223-229 (2016)
4. H. Zhong, Y. Wei-Wei, Rotating Bending Fatigue Property of LZ50 Steel Axle. Materials for Mechanical Engineering 36(1), 94-96, 100 (2012)
5. B. Yang, Y. Zhao, Influence of Surface Rolling Time on Short Fatigue Crack Behavior of LZ50 Axle Steel 13th International Conference on Fracture, Beijing, China
6. Y. Huo, B. Wang, J. Lin, Q. Bai, H. Ji, X. Tang, Hot compression deformation behavior and microstructure evolution rule of a high-speed railway axle steel. Indian J. Eng. Mater. S. 24(6), 447-454 (2017)
7. Z. Jin-Wen, W. Wen-Xian, G. Jianbing, C. Sheng-Wei, W. Yu-Tian, W. Zhi-Xiang, Z. Zhi-Gang, Hot deformation behavior and hot processing map of high speed axle steel DZ2. Transactions of Materials and Heat Treatment 41(10), 123-129 (2020)
8. S. Du, S. Chen, J. Song, Y. Li, Hot Deformation Behavior and Dynamic Recrystallization of Medium Carbon LZ50 Steel. Metall. Mater. Trans. A 48A(3), 1310-1320 (2017)
9. Z. Xiaohua, B. Yongqing, J. Xiaobin, Hot deformation behavior and high temperature plastic constitutive equation of LZ50 steel for axle. Heat Treatment of Metals 45(10), 31-34 (2020)
10. C. Zener, J.H. Hollomon, Effect of Strain Rate Upon Plastic Flow of Steel. J. Appl. Phys. 15(1), 22-32 (1944)
11. B. L, Modeling the Microstructural Evolution during Hot Deformation of Microalloyed Steels, Royal institute of technology (2009)
12. S.C. M, M.W. J, Study on the mechanism of hot deformation. Acta Metallurgica 14(9), 1136-1140 (1966)
13. C.M. Sellars, Modelling microstructural development during hot rolling. Material Science and Technology 6(11), 1072-1081 (1990)
14. Y. Lin, M. Chen, Numerical simulation and experimental verification of microstructure evolution in a three-dimensional hot upsetting process. J. Mater. Process. Tech. 209(9), 4578-4583 (2009)
15. F. Wei, X. Fujia, Microstructure evolution and dynamic recrystallization model of 20CrMnTiH steel during hot compression. Journal Of Plasticity engineering 21(03), 78-84 (2014)
16. Y. Xingsheng, W. Chuan, S. Ruxing, W. Yuchanag, W. Zhe, Microstructure evolution of 55NiCrMoV7 die steel during forging
processing: Experiment and simulation. Journal Of Plasticity Engineering 28(06), 174-184 (2021)
17. H. Youlin, W. Jianbo, L. Xueshi, Z. Xiyan, L. Baifeng, L. Qing, H. Guangjie, Research Development of Hot Processing Map Theory. Materials Reports 22(S3), 173-176 (2008)
18. R. Raj, Development of a Processing Map for Use in Warm-Forming and Hot-Forming Processes. Metallurgical Transactions A 12(6), 1089-1097 (1981)
19. Y.V.R.K. Prasad, H.L. Gegel, J.C. Malas, J.T. Morgan, K.A. Lark, S.M. Doraivelu, D.R. Barker, Modeling of dynamic material behavior in hot deformation: Forging of Ti-6242. Metallurgical transactions. A, Physical metallurgy and materials science 15(10), 1883-1892 (1984)