The strengthening mechanisms of hot-rolled steels micro alloyed with Ti （ST-TQS00） and Nh Ti （NT TQ500） were investigated by examining the microstructures of steels using optical microscope （OM）, scanning elec t...The strengthening mechanisms of hot-rolled steels micro alloyed with Ti （ST-TQS00） and Nh Ti （NT TQ500） were investigated by examining the microstructures of steels using optical microscope （OM）, scanning elec tron microscope （SEM） and transmission electron microscope （TEM）. The results revealed ahnost no differences in the solute solution strengthening and fine grained strengthcning of the two steels, whereas the contributions of pre cipitation strengthening and dislocation strengthening were different for ST-TQ500 and NT-TQ500. The measured precipitation strengthening effect of ST-TQ500 was 88 MPa higher than that of NT-TQ500： this difference was pri marily attributed to the stronger precipitation effect of thc Ti-containing nanoscale particles. The dislocation strengthening effect of ST TQ500 was approximately 80 MPa lower than that of NT-TQ500. This is tbought to be related to differences in deformation behavior during the finishing rolling stage; the inhibition of dynamic recrystallization from Nb in NT-TQ500 （Nb-Ti） may lead to higher density of dislocations in the microstructure.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Item Sponsored by National Natural Science Foundation of China(51374151)Foundation for Key Program of Shanxi Province of China(20111101053)Foundation for Major Coal Base New Materials Program of Shanxi Province of China(MC2014-02)
文摘The strengthening mechanisms of hot-rolled steels micro alloyed with Ti （ST-TQS00） and Nh Ti （NT TQ500） were investigated by examining the microstructures of steels using optical microscope （OM）, scanning elec tron microscope （SEM） and transmission electron microscope （TEM）. The results revealed ahnost no differences in the solute solution strengthening and fine grained strengthcning of the two steels, whereas the contributions of pre cipitation strengthening and dislocation strengthening were different for ST-TQ500 and NT-TQ500. The measured precipitation strengthening effect of ST-TQ500 was 88 MPa higher than that of NT-TQ500： this difference was pri marily attributed to the stronger precipitation effect of thc Ti-containing nanoscale particles. The dislocation strengthening effect of ST TQ500 was approximately 80 MPa lower than that of NT-TQ500. This is tbought to be related to differences in deformation behavior during the finishing rolling stage; the inhibition of dynamic recrystallization from Nb in NT-TQ500 （Nb-Ti） may lead to higher density of dislocations in the microstructure.
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.
