The effect of intercritical deformation on retained austenite and tensile performance of a low-carbon Si-Mn steel in modified quenching and bainitic partitioning processes was evaluated.The results showed that the int...The effect of intercritical deformation on retained austenite and tensile performance of a low-carbon Si-Mn steel in modified quenching and bainitic partitioning processes was evaluated.The results showed that the intercritical deformation can play a positive role in stabilizing and refining the retained austenite,and possessed promising potential in balancing tensile strength and ductility of multiphase high-strength steels.The experimental low-carbon Si-Mn steel exhibited multiphase configuration comprising polygonal ferrite,granular bainite and granular structure after two different modified quenching and bainitic partitioning processes,and the bainitic ferrite laths got refined by intercritical deformation.The volume fraction of retained austenite in film-like and blocky morphology was increased from 11.5%to 13.9%due to applied intercritical deformation,and the larger amount of retained austenite provided the sufficient transformation-induced plasticity effect and resulted in enhanced work hardening degree;in response,enhanced ultimate tensile strength 1260 MPa and fracture elongation 22.1%were obtained,leading to increased product of strength and elongation in value of 27.7 GPa% compared to 20.8 GPa% of undeformed structure.展开更多
The ultra-fine-grained ferrite(UFGF) with the size of less than 1 μm is often difficult to be obtained for low-alloyed steel in practical production processing.In this study,considering the rod and wire production pr...The ultra-fine-grained ferrite(UFGF) with the size of less than 1 μm is often difficult to be obtained for low-alloyed steel in practical production processing.In this study,considering the rod and wire production process,a new method for preparing the UFGF with submicron scale is proposed by warm deformation of six passes with total strain of 2.6,followed by the cooling process in Gleeble-3500 thermo-mechanical simulator.The results show that the UFGF with an average size of 0.64 μm could be obtained via the phase transformation from austenite grains with an average size of 3.4 μm,which are achieved by the deformation-induced reversal austenization during the high strain rate warm deformation.The main driving force for the reversal transformation is the stress.And the interval between the passes also plays an important role in the reversal austenization.展开更多
基金National Natural Science Foundation of China(Nos.51574107 and U1860105)Natural Science Foundation of Hebei Province(No.E2017209048)Science and Technology Research Project for Institutions of Higher Learning of Hebei Province(No.ZD2019064)for grant and financial support.
文摘The effect of intercritical deformation on retained austenite and tensile performance of a low-carbon Si-Mn steel in modified quenching and bainitic partitioning processes was evaluated.The results showed that the intercritical deformation can play a positive role in stabilizing and refining the retained austenite,and possessed promising potential in balancing tensile strength and ductility of multiphase high-strength steels.The experimental low-carbon Si-Mn steel exhibited multiphase configuration comprising polygonal ferrite,granular bainite and granular structure after two different modified quenching and bainitic partitioning processes,and the bainitic ferrite laths got refined by intercritical deformation.The volume fraction of retained austenite in film-like and blocky morphology was increased from 11.5%to 13.9%due to applied intercritical deformation,and the larger amount of retained austenite provided the sufficient transformation-induced plasticity effect and resulted in enhanced work hardening degree;in response,enhanced ultimate tensile strength 1260 MPa and fracture elongation 22.1%were obtained,leading to increased product of strength and elongation in value of 27.7 GPa% compared to 20.8 GPa% of undeformed structure.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 51574107, 51501056, 51975593)the Natural Science Foundation of Hebei Province (Grant Nos. E2015209243, E2017209048)+1 种基金the Liaoning Provincial Natural Science Foundation of China (Grant No. 2019-KF-25-01)the Research Funds from Department of Education of Hebei Province (Grant Nos. QN2019051, ZD 2019064).
文摘The ultra-fine-grained ferrite(UFGF) with the size of less than 1 μm is often difficult to be obtained for low-alloyed steel in practical production processing.In this study,considering the rod and wire production process,a new method for preparing the UFGF with submicron scale is proposed by warm deformation of six passes with total strain of 2.6,followed by the cooling process in Gleeble-3500 thermo-mechanical simulator.The results show that the UFGF with an average size of 0.64 μm could be obtained via the phase transformation from austenite grains with an average size of 3.4 μm,which are achieved by the deformation-induced reversal austenization during the high strain rate warm deformation.The main driving force for the reversal transformation is the stress.And the interval between the passes also plays an important role in the reversal austenization.
