The hot deformation behaviors of GCr15 bearing steel were investigated by isothermal compression tests, performed on a Gleeble-3800 thermal-mechanical simulator at temperatures between 950 ℃ and 1 150 ℃ and strain r...The hot deformation behaviors of GCr15 bearing steel were investigated by isothermal compression tests, performed on a Gleeble-3800 thermal-mechanical simulator at temperatures between 950 ℃ and 1 150 ℃ and strain rates between 0.1 and 10 s-1. The peak stress and peak strain as functions of processing parameters were obtained. The dependence of peak stress on strain rate and temperature obeys a hyperbolic sine equation with a Zener-Hollomon parameter. By regression analysis, in the temperature range of 950-1 150 ℃ and strain rate range of 0.1?10 s?1, the mean activation energy and the stress exponent were determined to be 351kJ/mol and 4.728, respectively. Meanwhile, models of flow stress and dynamic recrystallization (DRX) grain size were also established. The model predictions show good agreement with experimental results.展开更多
Effect of tin and antimony on hot ductility of GCr15 bearing steel as well as interaction between lanthanum and tramp elements, were studied by simulator Gleeble-1500 and the fractures for the tested steels were analy...Effect of tin and antimony on hot ductility of GCr15 bearing steel as well as interaction between lanthanum and tramp elements, were studied by simulator Gleeble-1500 and the fractures for the tested steels were analyzed using SEM and EDS. The results show that with increasing contents of tin and antimony elements, the hot ductility of GCr15 bearing steel was decreased. Lanthanum can reduce the harmful effect of tramp elements on the hot ductility of GCr15, which can react with antimony to form compound and segregate at grain boundary in steel. Lanthanum can refine the recrystallized austenite grains after deformation and subsequent martensite structure.展开更多
To further improve the metallurgical quality of electroslag remelting,remove the large inclusions in electroslag ingot and refine the solidification structure of electroslag ingot,an electroslag remelting furnace with...To further improve the metallurgical quality of electroslag remelting,remove the large inclusions in electroslag ingot and refine the solidification structure of electroslag ingot,an electroslag remelting furnace with electromagnetic stirring was designed,and the influence of different magnetic induction intensities on metallurgical quality of GCr15 electroslag ingot was studied.Inclusions with different sizes and types were analyzed by an ASPEX scanning electron microscope,and the morphology and composition of inclusions were further observed by a JSM-6510LV scanning electron microscope.The distribution of alloying elements on the cross section of electroslag ingot was analyzed by original position analysis(OPA).The results show that whether or not electromagnetic stirring is used,the inclusions in electroslag ingot are mainly composed of Al_(2)O_(3),MnS,MnS-oxide and other oxides,among which Al_(2)O_(3) is the most.Compared with an electroslag ingot without electromagnetic stirring,the number of inclusions decreases considerably,and the proportion of small inclusions increases while the proportion of large inclusions decreases when the electromagnetic stirring with remelting current of 1.1 kA and magnetic induction intensity of 62 Gs is applied.However,excessive electromagnetic force will cause the number and diameter of inclusions to increase again.Electromagnetic stirring has different effects on the segregation of different elements.Under the experimental conditions,the weak electromagnetic force with 1.1 kA and magnetic induction intensity of 108 Gs has little effect on the segregation of C,but decreases the segregation of P,and the excessive electromagnetic force aggravates the segregation of alloy elements.展开更多
The effect of the axial static magnetic field(ASMF)on cleanliness and microstructure in magnetically controlled electroslag remelted GCr15 bearing steel ingots was investigated experimentally.The results show that a m...The effect of the axial static magnetic field(ASMF)on cleanliness and microstructure in magnetically controlled electroslag remelted GCr15 bearing steel ingots was investigated experimentally.The results show that a magnetically controlled spin-vibration induced by the interaction of the ASMFs and the remelting current exists at the consumable electrode tip,resulting in thinner liquid melt film and smaller droplets.With the increase in magnetic flux density,the optimization effect of ASMFs on electroslag remelting process increases and reaches the peak with a 40 mT ASMF,then decreases.The cleanliness of the ingots was improved,and the count of inclusions larger than 5μm was reduced.The microstructure of the ingots processed with a 40 mT ASMF was significantly refined.The depth of the metallic molten pool was reduced from 45.2 to 17.5 mm with the application of 40 mT ASMF.The tensile strength,impact toughness,and Rockwell hardness of the ingots obtained under the 40 mT ASMF were significantly improved.The mechanisms of the spin-vibration occurring at the electrode tip end were interpreted in detail to elucidate the effect of ASMFs.展开更多
基金Project(2001-122) supported by the Youth Science and Technology Elitist Foundation of Dalian, China
文摘The hot deformation behaviors of GCr15 bearing steel were investigated by isothermal compression tests, performed on a Gleeble-3800 thermal-mechanical simulator at temperatures between 950 ℃ and 1 150 ℃ and strain rates between 0.1 and 10 s-1. The peak stress and peak strain as functions of processing parameters were obtained. The dependence of peak stress on strain rate and temperature obeys a hyperbolic sine equation with a Zener-Hollomon parameter. By regression analysis, in the temperature range of 950-1 150 ℃ and strain rate range of 0.1?10 s?1, the mean activation energy and the stress exponent were determined to be 351kJ/mol and 4.728, respectively. Meanwhile, models of flow stress and dynamic recrystallization (DRX) grain size were also established. The model predictions show good agreement with experimental results.
文摘Effect of tin and antimony on hot ductility of GCr15 bearing steel as well as interaction between lanthanum and tramp elements, were studied by simulator Gleeble-1500 and the fractures for the tested steels were analyzed using SEM and EDS. The results show that with increasing contents of tin and antimony elements, the hot ductility of GCr15 bearing steel was decreased. Lanthanum can reduce the harmful effect of tramp elements on the hot ductility of GCr15, which can react with antimony to form compound and segregate at grain boundary in steel. Lanthanum can refine the recrystallized austenite grains after deformation and subsequent martensite structure.
基金financially supported by the National Natural Science Foundation of China(51774003/52074002/51974002)the Ministry of Industry and Information Technology(TC190A4DA-35)。
文摘To further improve the metallurgical quality of electroslag remelting,remove the large inclusions in electroslag ingot and refine the solidification structure of electroslag ingot,an electroslag remelting furnace with electromagnetic stirring was designed,and the influence of different magnetic induction intensities on metallurgical quality of GCr15 electroslag ingot was studied.Inclusions with different sizes and types were analyzed by an ASPEX scanning electron microscope,and the morphology and composition of inclusions were further observed by a JSM-6510LV scanning electron microscope.The distribution of alloying elements on the cross section of electroslag ingot was analyzed by original position analysis(OPA).The results show that whether or not electromagnetic stirring is used,the inclusions in electroslag ingot are mainly composed of Al_(2)O_(3),MnS,MnS-oxide and other oxides,among which Al_(2)O_(3) is the most.Compared with an electroslag ingot without electromagnetic stirring,the number of inclusions decreases considerably,and the proportion of small inclusions increases while the proportion of large inclusions decreases when the electromagnetic stirring with remelting current of 1.1 kA and magnetic induction intensity of 62 Gs is applied.However,excessive electromagnetic force will cause the number and diameter of inclusions to increase again.Electromagnetic stirring has different effects on the segregation of different elements.Under the experimental conditions,the weak electromagnetic force with 1.1 kA and magnetic induction intensity of 108 Gs has little effect on the segregation of C,but decreases the segregation of P,and the excessive electromagnetic force aggravates the segregation of alloy elements.
基金This work is supported by the National Key Research and Development Program of China under Grant numbers of 2016YFB0300401,2018YFF0109404,and 2016YFB0301401the National Natural Science Foundation of China under Grant numbers of U1860202,U1732276,50134010,51704193,51904184,and 52004156the Users with Excellence Program of Hefei Science Center CAS under Grant number of 2019HSC-UE010,and the Changjiang Scholar Program of Chinese Ministry of Education.
文摘The effect of the axial static magnetic field(ASMF)on cleanliness and microstructure in magnetically controlled electroslag remelted GCr15 bearing steel ingots was investigated experimentally.The results show that a magnetically controlled spin-vibration induced by the interaction of the ASMFs and the remelting current exists at the consumable electrode tip,resulting in thinner liquid melt film and smaller droplets.With the increase in magnetic flux density,the optimization effect of ASMFs on electroslag remelting process increases and reaches the peak with a 40 mT ASMF,then decreases.The cleanliness of the ingots was improved,and the count of inclusions larger than 5μm was reduced.The microstructure of the ingots processed with a 40 mT ASMF was significantly refined.The depth of the metallic molten pool was reduced from 45.2 to 17.5 mm with the application of 40 mT ASMF.The tensile strength,impact toughness,and Rockwell hardness of the ingots obtained under the 40 mT ASMF were significantly improved.The mechanisms of the spin-vibration occurring at the electrode tip end were interpreted in detail to elucidate the effect of ASMFs.
