The thermoplasticity of duplex stainless steel 2205（DSS2205） is better than that of lean duplex steel 2101（LDX2101）, which undergoes severe cracking during hot rolling. The microstructure, microhardness, phase rat...The thermoplasticity of duplex stainless steel 2205（DSS2205） is better than that of lean duplex steel 2101（LDX2101）, which undergoes severe cracking during hot rolling. The microstructure, microhardness, phase ratio, and recrystallization dependence of the deformation compatibility of LDX2101 and DSS2205 were investigated using optical microscopy（OM）, electron backscatter diffraction（EBSD）, Thermo-Calc software, and transmission electron microscopy（TEM）. The results showed that the phase-ratio transformations of LDX2101 and DSS2205 were almost equal under the condition of increasing solution temperature. Thus, the phase transformation was not the main cause for the hot plasticity difference of these two steels. The grain size of LDX2101 was substantially greater than that of DSS2205, and the microhardness difference of LDX2101 was larger than that of DSS2205. This difference hinders the transfer of strain from ferrite to austenite. In the rolling process, the ferrite grains of LDX2101 underwent continuous softening and were substantially refined. However, although little recrystallization occurred at the boundaries of austenite, serious deformation accumulated in the interior of austenite, leading to a substantial increase in hardness. The main cause of crack formation is the microhardness difference between ferrite and austenite.展开更多
The microstructures and impact absorbed energies at various temperatures were investigated for steel strips hot rolled to thickness reductions of 95.5%, 96.0%, 96.5%, 97.0%, and 97.5%. Results indicate that grain refi...The microstructures and impact absorbed energies at various temperatures were investigated for steel strips hot rolled to thickness reductions of 95.5%, 96.0%, 96.5%, 97.0%, and 97.5%. Results indicate that grain refinement can be realized with an increase in hot rolling reduction. Besides, finer precipitates can be achieved with an increase in hot rolling reduction from 95.5%to 97.0%. The impact absorbed energy decreases with a decrease in testing temperature for steel strips hot rolled to 95.5%, 96.0%, and 96.5%reductions in thickness. However, in the case of steel strips hot rolled to 97.0%and 97.5%reductions in thickness, the impact absorbed energy remained almost constant with a decrease in testing temperature.展开更多
For strip steel with the thickness of 1.6 ram, the yield and tensile strengths as high as 760 and 850 MPa, respectively, were achieved using the compact strip production technology. Precipitates in the steel were char...For strip steel with the thickness of 1.6 ram, the yield and tensile strengths as high as 760 and 850 MPa, respectively, were achieved using the compact strip production technology. Precipitates in the steel were characterized by scanning and transmission electron microscopy to elucidate the strengthening mechanism. In addition, intragranular misorientation, Kernel average misorientafion, and stored energy were measured using electron backscatter diffraction for crystallographic analysis of ferrite grains containing precipitates and their neighbors without precipitates. It is found that precipitates in specimens primarily consist of TiC and Ti4CzS2. Ferrite grains containing pre- cipitates exhibit the high Taylor factor as well as the crystallographic orientations with {012}, {011}, {112}, or {221} plane parallel to the rolling plane. Compared with the intragranular orientation of adjoining grains, the intragranular misorientation of grains containing precipi- tates fluctuates more frequently and more mildly as a function of distance. Moreover, the precipitates can induce ferrite grains to store a rela- tively large amount of energy. These results suggest that a correlation exists between precipitation in ferrite grains and grain crystallographic properties.展开更多
The composition and production technology of the type of hot-rolled steel plate used in two-sided enameling were briefly described. The microstructure and mechanical properties before and after enameling were contrast...The composition and production technology of the type of hot-rolled steel plate used in two-sided enameling were briefly described. The microstructure and mechanical properties before and after enameling were contrastively investigated,and the precipitates in the samples were analyzed using transmission electron microscope and energy dispersive spectrometer. The results show the ferrite grain size of the steel plate after high-temperature enamel firing to be fine,with a large number of TiC and Ti;C;S;precipitates dispersed throughout the ferrite matrix. After two rounds of enamel firing at a temperature range of 800-890 ℃,its yield strength can still reach342 MPa. The results of a hydrogen permeation test show that the hydrogen storage properties of the steel plate are much better than those of ordinary structural carbon steel. A better bubble structure in the enamel layer can be obtained by this steel plate,with no fish-scale defects on the enameled steel-plate surface.展开更多
The critical transformation temperatures,A_(c1) and A_(c3),of a hot-rolled low-carbon titanium microalloyed steel were determined as a part of an examination of its phase-transformation behavior. Austenite decompositi...The critical transformation temperatures,A_(c1) and A_(c3),of a hot-rolled low-carbon titanium microalloyed steel were determined as a part of an examination of its phase-transformation behavior. Austenite decomposition during the continuous cooling of the titanium microalloyed steel was studied by heating it to 1 250 ℃,cooling it to 880 ℃,holding for 2 s,and then cooling it to room temperature at different cooling rates. The transformation kinetics( CCT curve) was characterized as well.展开更多
The extruded Mg-12Gd-3Y-0.4Zr alloy sheets were rolled from 30 mm to 2.3 mm at 723 K by electric heated rollers,and then different heat treatments were performed to improve their properties.The microstructures and ten...The extruded Mg-12Gd-3Y-0.4Zr alloy sheets were rolled from 30 mm to 2.3 mm at 723 K by electric heated rollers,and then different heat treatments were performed to improve their properties.The microstructures and tensile properties of the alloy sheets were investigated,including as-rolled,annealed and T5 treated.The experimental results show that the grains are effectively refined by the rolling process,and the strength of the rolled alloy is greatly enhanced.The annealed alloy exhibits lower strength and higher elongation than the rolled one,while the aged alloy shows higher strength and lower elongation.After being aged at 498 K for 17 h,the alloys get the highest strength,namely,the ultimate tensile strength is 456.8 MPa,yield strength is 348.9 MPa,and elongation is 3.8%.展开更多
A short process without solution treatment was developed to manufacture Cu-2.3Fe-0.03 P alloy strips. After hot rolling-quenching and cold rolling with 80% reduction, the alloy exhibited excellent resistance to recrys...A short process without solution treatment was developed to manufacture Cu-2.3Fe-0.03 P alloy strips. After hot rolling-quenching and cold rolling with 80% reduction, the alloy exhibited excellent resistance to recrystallization softening. The hardness and electrical conductivity of Cu-Fe-P alloy under different thermomechanical treatments were measured by hardness tester and double bridge tester, respectively, and the microstructure of the alloy was examined by optical microscopy and transmission electron microscopy. The results show that the finished product of Cu-2.3Fe-0.03 P alloy was strengthened by work hardening, while the Fe precipitates with the size of about 25 nm stabilized the cold rolled structure. The conductivity decreased during cold rolling, especially for the pre-aged specimens, because the fine precipitates with the size smaller than 5 nm re-dissolved easily into the matrix. A Cu-Fe-P alloy with an electrical conductivity of 66% IACS and a hardness of HV 134 can be gained.展开更多
研究了模拟薄板坯连铸连轧工艺(Thin Slab Casting and Rolling)生产Ti-IF钢的析出行为。利用透射电镜分析了铸坯连续快速冷却及热连轧过程Ti-IF钢中第二相粒子的析出行为特征,将TiS,Ti4C2S2等析出粒子的尺寸、分布及数量分别与传统工...研究了模拟薄板坯连铸连轧工艺(Thin Slab Casting and Rolling)生产Ti-IF钢的析出行为。利用透射电镜分析了铸坯连续快速冷却及热连轧过程Ti-IF钢中第二相粒子的析出行为特征,将TiS,Ti4C2S2等析出粒子的尺寸、分布及数量分别与传统工艺的析出物进行了分析比较。结果表明,TSCR生产的Ti-IF钢析出物比传统工艺更为粗大,且发现有较粗大的TiC和Ti4C2S2的复合析出物。展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51174026)the National Science and Technology Pillar Program during the Twelfth Five-Year Plan Period (No. 2012BAE04B02)
文摘The thermoplasticity of duplex stainless steel 2205（DSS2205） is better than that of lean duplex steel 2101（LDX2101）, which undergoes severe cracking during hot rolling. The microstructure, microhardness, phase ratio, and recrystallization dependence of the deformation compatibility of LDX2101 and DSS2205 were investigated using optical microscopy（OM）, electron backscatter diffraction（EBSD）, Thermo-Calc software, and transmission electron microscopy（TEM）. The results showed that the phase-ratio transformations of LDX2101 and DSS2205 were almost equal under the condition of increasing solution temperature. Thus, the phase transformation was not the main cause for the hot plasticity difference of these two steels. The grain size of LDX2101 was substantially greater than that of DSS2205, and the microhardness difference of LDX2101 was larger than that of DSS2205. This difference hinders the transfer of strain from ferrite to austenite. In the rolling process, the ferrite grains of LDX2101 underwent continuous softening and were substantially refined. However, although little recrystallization occurred at the boundaries of austenite, serious deformation accumulated in the interior of austenite, leading to a substantial increase in hardness. The main cause of crack formation is the microhardness difference between ferrite and austenite.
文摘The microstructures and impact absorbed energies at various temperatures were investigated for steel strips hot rolled to thickness reductions of 95.5%, 96.0%, 96.5%, 97.0%, and 97.5%. Results indicate that grain refinement can be realized with an increase in hot rolling reduction. Besides, finer precipitates can be achieved with an increase in hot rolling reduction from 95.5%to 97.0%. The impact absorbed energy decreases with a decrease in testing temperature for steel strips hot rolled to 95.5%, 96.0%, and 96.5%reductions in thickness. However, in the case of steel strips hot rolled to 97.0%and 97.5%reductions in thickness, the impact absorbed energy remained almost constant with a decrease in testing temperature.
文摘For strip steel with the thickness of 1.6 ram, the yield and tensile strengths as high as 760 and 850 MPa, respectively, were achieved using the compact strip production technology. Precipitates in the steel were characterized by scanning and transmission electron microscopy to elucidate the strengthening mechanism. In addition, intragranular misorientation, Kernel average misorientafion, and stored energy were measured using electron backscatter diffraction for crystallographic analysis of ferrite grains containing precipitates and their neighbors without precipitates. It is found that precipitates in specimens primarily consist of TiC and Ti4CzS2. Ferrite grains containing pre- cipitates exhibit the high Taylor factor as well as the crystallographic orientations with {012}, {011}, {112}, or {221} plane parallel to the rolling plane. Compared with the intragranular orientation of adjoining grains, the intragranular misorientation of grains containing precipi- tates fluctuates more frequently and more mildly as a function of distance. Moreover, the precipitates can induce ferrite grains to store a rela- tively large amount of energy. These results suggest that a correlation exists between precipitation in ferrite grains and grain crystallographic properties.
文摘The composition and production technology of the type of hot-rolled steel plate used in two-sided enameling were briefly described. The microstructure and mechanical properties before and after enameling were contrastively investigated,and the precipitates in the samples were analyzed using transmission electron microscope and energy dispersive spectrometer. The results show the ferrite grain size of the steel plate after high-temperature enamel firing to be fine,with a large number of TiC and Ti;C;S;precipitates dispersed throughout the ferrite matrix. After two rounds of enamel firing at a temperature range of 800-890 ℃,its yield strength can still reach342 MPa. The results of a hydrogen permeation test show that the hydrogen storage properties of the steel plate are much better than those of ordinary structural carbon steel. A better bubble structure in the enamel layer can be obtained by this steel plate,with no fish-scale defects on the enameled steel-plate surface.
文摘The critical transformation temperatures,A_(c1) and A_(c3),of a hot-rolled low-carbon titanium microalloyed steel were determined as a part of an examination of its phase-transformation behavior. Austenite decomposition during the continuous cooling of the titanium microalloyed steel was studied by heating it to 1 250 ℃,cooling it to 880 ℃,holding for 2 s,and then cooling it to room temperature at different cooling rates. The transformation kinetics( CCT curve) was characterized as well.
基金Project(2007CB613703)supported by the Major State Basic Research Program of ChinaProject(06DJ14005)supported by the ShanghaiCouncil of Science and Technology,China
文摘The extruded Mg-12Gd-3Y-0.4Zr alloy sheets were rolled from 30 mm to 2.3 mm at 723 K by electric heated rollers,and then different heat treatments were performed to improve their properties.The microstructures and tensile properties of the alloy sheets were investigated,including as-rolled,annealed and T5 treated.The experimental results show that the grains are effectively refined by the rolling process,and the strength of the rolled alloy is greatly enhanced.The annealed alloy exhibits lower strength and higher elongation than the rolled one,while the aged alloy shows higher strength and lower elongation.After being aged at 498 K for 17 h,the alloys get the highest strength,namely,the ultimate tensile strength is 456.8 MPa,yield strength is 348.9 MPa,and elongation is 3.8%.
基金Project supported by Central South University Postdoctoral Science FoundationProject(CSUZC2013019)supported by the Open Fund for the Precision Instruments of Central South University,ChinaProject(CSUZC201522)supported by the Open-End Fund for the Valuable and Precision Instruments of Central South University,China
文摘A short process without solution treatment was developed to manufacture Cu-2.3Fe-0.03 P alloy strips. After hot rolling-quenching and cold rolling with 80% reduction, the alloy exhibited excellent resistance to recrystallization softening. The hardness and electrical conductivity of Cu-Fe-P alloy under different thermomechanical treatments were measured by hardness tester and double bridge tester, respectively, and the microstructure of the alloy was examined by optical microscopy and transmission electron microscopy. The results show that the finished product of Cu-2.3Fe-0.03 P alloy was strengthened by work hardening, while the Fe precipitates with the size of about 25 nm stabilized the cold rolled structure. The conductivity decreased during cold rolling, especially for the pre-aged specimens, because the fine precipitates with the size smaller than 5 nm re-dissolved easily into the matrix. A Cu-Fe-P alloy with an electrical conductivity of 66% IACS and a hardness of HV 134 can be gained.
文摘研究了模拟薄板坯连铸连轧工艺(Thin Slab Casting and Rolling)生产Ti-IF钢的析出行为。利用透射电镜分析了铸坯连续快速冷却及热连轧过程Ti-IF钢中第二相粒子的析出行为特征,将TiS,Ti4C2S2等析出粒子的尺寸、分布及数量分别与传统工艺的析出物进行了分析比较。结果表明,TSCR生产的Ti-IF钢析出物比传统工艺更为粗大,且发现有较粗大的TiC和Ti4C2S2的复合析出物。
