The effects of deforming temperatures on the tensile behaviors of quenching and partitioning treated steels were investigated. It was found that the ultimate tensile strength of the steel decreased with the increasing...The effects of deforming temperatures on the tensile behaviors of quenching and partitioning treated steels were investigated. It was found that the ultimate tensile strength of the steel decreased with the increasing temperature from 25 to 100 ℃, reached the maximum value at 300 ℃, and then declined by a significant extent when the temperature further reached 400 ℃. The total elongations at 100, 200 and 300 ℃are at about the same level. The steel achieved optimal mechanical properties at 300 ℃due to the proper transformation behavior of retained austenite since the stability of retained austenite is largely dependent on the deforming temperature. When tested at 100 and 200 ℃, the retained aus tenite was reluctant to transform, while at the other temperatures, about 10 vol. % of retained aus- tenite transformed during the tensile tests. The relationship between the stability of retained austenite and the work hardening behavior of quenching and partitioning treated steels at different deforming temperatures was also studied and discussed in detail. In order to obtain excellent mechanical properties, the stability of retained austenite should be carefully controlled so that the effect of transforma tion-induced plasticity could take place continuously during plastic deformation.展开更多
A combined process of hot-deformation plus two-step quenching and partitioning （HDQP） treatment was applied to a low carbon 20Si2CrNi3MoV steel, and transmission electron microscopy （TEM）, scanning electron micros...A combined process of hot-deformation plus two-step quenching and partitioning （HDQP） treatment was applied to a low carbon 20Si2CrNi3MoV steel, and transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, Vickers hardness and tension test were used to characterize the microstructure and mechanical properties. More stable retained austen ite due to fine microstructures and typical curved micromorphology is obtained, and the newly-treated steel obtains more retained austenite because of the effect of hot deformation. The retained austenite fraction increases and then decreases with the increasing quenching temperature from 200 to 350 ℃. The maximum retained austenite fraction （18.3 % ） and elongation （15 % ） are obtained to enhance the ductility.展开更多
基金financial support of the National Key Research and Development Program of China(No.2017YFB0304401)National Natural Science Foundation of China(Nos.U1564203,51571141 and 51201105)the support provided by Shanghai Key Laboratory of Materials Laser Processing and Modification,Shanghai Jiao Tong University
文摘The effects of deforming temperatures on the tensile behaviors of quenching and partitioning treated steels were investigated. It was found that the ultimate tensile strength of the steel decreased with the increasing temperature from 25 to 100 ℃, reached the maximum value at 300 ℃, and then declined by a significant extent when the temperature further reached 400 ℃. The total elongations at 100, 200 and 300 ℃are at about the same level. The steel achieved optimal mechanical properties at 300 ℃due to the proper transformation behavior of retained austenite since the stability of retained austenite is largely dependent on the deforming temperature. When tested at 100 and 200 ℃, the retained aus tenite was reluctant to transform, while at the other temperatures, about 10 vol. % of retained aus- tenite transformed during the tensile tests. The relationship between the stability of retained austenite and the work hardening behavior of quenching and partitioning treated steels at different deforming temperatures was also studied and discussed in detail. In order to obtain excellent mechanical properties, the stability of retained austenite should be carefully controlled so that the effect of transforma tion-induced plasticity could take place continuously during plastic deformation.
基金supported by the National Key Research and Development Plan(Nos.2017YFB0304401 and 2016YFB0101605)the Major State Basic Research Development Program of China(973Program)(No.2010CB630803)
文摘A combined process of hot-deformation plus two-step quenching and partitioning （HDQP） treatment was applied to a low carbon 20Si2CrNi3MoV steel, and transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, Vickers hardness and tension test were used to characterize the microstructure and mechanical properties. More stable retained austen ite due to fine microstructures and typical curved micromorphology is obtained, and the newly-treated steel obtains more retained austenite because of the effect of hot deformation. The retained austenite fraction increases and then decreases with the increasing quenching temperature from 200 to 350 ℃. The maximum retained austenite fraction （18.3 % ） and elongation （15 % ） are obtained to enhance the ductility.
