Zhi-qiang Yang 1 . Zheng-dong Liu 1 . Xi-kou He 1 . Shi-bin Qiao 1 . Chang-sheng Xie 1,2
1 Institute for Special Steels, Central Iron and Steel Research Institute Group, Beijing 100081, China 2 School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
Zhi-qiang Yang 1 . Zheng-dong Liu 1 . Xi-kou He 1 . Shi-bin Qiao 1 . Chang-sheng Xie 1,2
1 Institute for Special Steels, Central Iron and Steel Research Institute Group, Beijing 100081, China 2 School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
摘要 Using a Gleeble–1500D thermal–mechanical simulator, the hot-deformation behavior and critical strain in the dynamic recrystallization of SA508Gr.4N steel were investigated by compression tests from 1050 to 1250 C with strain rates from 0.001 to 0.1 s -1. Stress–strain curves were fitted by a nonlinear fitting method. Based on these tests, the flow stress constitutive equations of the work-hardening dynamical recovery period and dynamical recrystallization period were established for SA508Gr.4N steel. The stress–strain curves of SA508Gr.4N steel predicted by the established models are in a good agreement with the experimental ones. Curves of ln? -? and -q(ln?)/q? -? (where his the work-hardening rate and e is true strain) were plotted from experimental data. A critical strain (?c) and a peak strain (?p) of dynamic recrystallization were obtained and exhibited a linear relationship, i.e., ?c = 0.386ep. The predicted model of ?c could be described by the equation of ?c = 1.604?10 -3Z0.127.
Abstract：Using a Gleeble–1500D thermal–mechanical simulator, the hot-deformation behavior and critical strain in the dynamic recrystallization of SA508Gr.4N steel were investigated by compression tests from 1050 to 1250 C with strain rates from 0.001 to 0.1 s -1. Stress–strain curves were fitted by a nonlinear fitting method. Based on these tests, the flow stress constitutive equations of the work-hardening dynamical recovery period and dynamical recrystallization period were established for SA508Gr.4N steel. The stress–strain curves of SA508Gr.4N steel predicted by the established models are in a good agreement with the experimental ones. Curves of ln? -? and -q(ln?)/q? -? (where his the work-hardening rate and e is true strain) were plotted from experimental data. A critical strain (?c) and a peak strain (?p) of dynamic recrystallization were obtained and exhibited a linear relationship, i.e., ?c = 0.386ep. The predicted model of ?c could be described by the equation of ?c = 1.604?10 -3Z0.127.
ZHI-QIANG,LIU Zheng-Dong,HE Xi-Kou, et al. ConstitutivemodelingandcriticalstrainofdynamicrecrystallizationinSA508Gr.4Nsteelforadvancedpressurevesselmaterials[J]. Journal of Iron and Steel Research International, 2018, 25(11): 1189-1197.
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