Currently, when magnesium alloy sheet is rolled, the method of controlling roll temperature is simple and inaccurate. Furthermore, roll temperature has a large influence on the quality of magnesium alloy sheet; theref...Currently, when magnesium alloy sheet is rolled, the method of controlling roll temperature is simple and inaccurate. Furthermore, roll temperature has a large influence on the quality of magnesium alloy sheet; therefore, a new model using circular fluid flow control roll temperature has been designed. A fluid heat transfer structure was designed, the heat transfer process model of the fluid heating roll was simplified, and the finite di erence method was used to cal?culate the heat transfer process. Fluent software was used to simulate the fluid?solid coupling heat transfer, and both the trend and regularity of the temperature field in the heat transfer process were identified. The results show that the heating e ciency was much higher than traditional heating methods(when the fluid heat of the roll and tempera?ture distribution of the roll surface was more uniform). Moreover, there was a bigger temperature di erence between the input and the output, and after using reverse flow the temperature di erence decreased. The axial and circum?ferential temperature distributions along the sheet were uniform. Both theoretical calculation results and numerical simulation results of the heat transfer between fluid and roll were compared. The error was 1.8%–12.3%, showing that the theoretical model can both forecast and regulate the temperature of the roll(for magnesium alloy sheets) in the rolling process.展开更多
In this study,accumulated extrusion bonding(AEB)process with application of artificial water cooling was successfully performed to fabricate fined-grains AZ31B Mg alloy sheets at 150℃,200℃ and 250℃.The resultant mi...In this study,accumulated extrusion bonding(AEB)process with application of artificial water cooling was successfully performed to fabricate fined-grains AZ31B Mg alloy sheets at 150℃,200℃ and 250℃.The resultant microstructure and mechanical properties are systematically investigated.It reveals that the processing temperature has an important effect on the microstructural evolution during extrusion.During AEB process at 150℃ and 200℃,{10-12}tensile twinning was activated at early stage of extrusion,and subsequently continuous dynamic recrystallization(CDRX)occurred and dominated the further deformation.However,for the sample extruded at 250℃,hardly any twins can be observed,and new fined dynamic recrystallized grains were found along grain boundaries.Artificial cooling was utilized to reduce the rate of grain growth out of the extrusion die,resulting the grains significantly refined from 11μm to 2.5μm.Local high dislocation density region was also observed in the microstructure of sample processed at 150℃ in artificial cooling condition,and the degree decreased with the processing temperature increase.The results summarized from tensile tests indicated that due to the grain refinement the strength and ductility was significantly enhanced(YS of 186 MPa vs.145 MPa,UTS of 391 MPa vs.336 MPa and FE of 31.5%vs.24.5%compared with the as-received sample).Subsequently,annealing treatment at different temperatures was applied to eliminate the high dislocation density.The sample annealed at 200℃ exhibited the best comprehensive mechanical property with YS of 179 MPa,UTS of 390 MPa and FE of 33.0%.As the annealing temperature increasing,the dislocation density was reduced by static recrystallization(SRX)and grain growth,leading to a decreased strength and ductility.展开更多
Temperature detection and tracking of AZ31B magnesium alloy plate during the air-cooling transport process were investigated and carried out under different thicknesses and initial temperatures.Experimental results sh...Temperature detection and tracking of AZ31B magnesium alloy plate during the air-cooling transport process were investigated and carried out under different thicknesses and initial temperatures.Experimental results show that there exists a sudden temperature drop in the range of 1/4 of width distanced from the edge.When the plate is cooled by 25-56°C,the maximum inhomogeneous temperature distribution under all process conditions will appear in width direction.For the air-cooling transport process,the temperature control model for predicting the average temperature of the Mg plate after a predetermined time period can be established by modifying the Stefan-Boltzmann empirical equation.The model mainly depends on the plate specifications and air-cooling time.展开更多
Highly textured Heusler alloy Mn_(46)Ni_(42)Sn_(11)Sb_1 ribbons were prepared by melt spinning. The annealed high Mn content Mn46Ni42Sn11Sb1 ribbon cross-section microstructure, crystal structure, martensitic transfor...Highly textured Heusler alloy Mn_(46)Ni_(42)Sn_(11)Sb_1 ribbons were prepared by melt spinning. The annealed high Mn content Mn46Ni42Sn11Sb1 ribbon cross-section microstructure, crystal structure, martensitic transformation(MT), and magnetoresistance(MR) properties were investigated. The MR in the annealed ribbon was assessed by the magnetic field direction perpendicular to the ribbon surface with the magnetic field up to 30 k Oe. The large negative value of 25% for MR was obtained at 244 K. The exchange bias(EB) effects of the as-spun and annealed ribbons were investigated. After annealing, the EB effects have been improved by about 25 Oe at the temperature of 50 K. The magnetizations have increased approximately by 10% more than the as-spun ribbon.展开更多
The crystal structure, phase transition, and magnetocaloric effect in Ni42.8Mn40.3Co5.7Sn11.2alloy are investigated by structure analysis and magnetic measurements. A large magnetic entropy change of 45.6 J/kg·K ...The crystal structure, phase transition, and magnetocaloric effect in Ni42.8Mn40.3Co5.7Sn11.2alloy are investigated by structure analysis and magnetic measurements. A large magnetic entropy change of 45.6 J/kg·K is obtained at 215 K under a magnetic field of 30 kOe(1 Oe = 79.5775 A·m-1). The effective refrigerant capacity of Ni42.8Mn40.3Co5.7Sn11.2alloy reaches 72.1 J/kg under an applied field changing from 0 to 30 kOe. The external magnetic field shifts the martensitic transition temperature about 3–4 K/10 kOe towards low temperature, indicating that magnetic field can retard the phase transition to a certain extent. The origin of large magnetic entropy change is discussed in the paper.展开更多
A decrease in the weight of aerospace vehicles,large ships,weapons,and high-speed trains will increase the demand for wide-width magnesium alloy plates and their composite parts to replace steel and plastic.An investi...A decrease in the weight of aerospace vehicles,large ships,weapons,and high-speed trains will increase the demand for wide-width magnesium alloy plates and their composite parts to replace steel and plastic.An investigation was conducted to study the variation in deformation behaviors along the transverse direction during the warm rolling of a 1480-mm-wide AZ31B plate.A uniaxial thermal compression test with a 59%reduction was performed at different positions on a 13.7-mm-thick rolled plate along the width direction at a temperature of 220℃ and 270℃ and strain rate of 15 s^(−1).At the same time,the 13.7-mm-thick plate was rolled in a single pass to 5.6 mm on a mill with a 1725-mm-wide roll to confirm the thermal deformation behavior and the dynamic recrystallization(DRX).The results show that the main texture type does not change and the grain size does not have a clear deflection when the magnesium alloy plate reaches a certain value under rolling accumulative reduction.The grain size of a 13.7-mm-thick plate increases with a decrease in the distance to the center layer in the thickness direction.In the width direction,the edge(R6)first decreases and then increases toward the symmetric plane(R1).The critical stress required for dynamic recrystallization in the transition zone R3 of the rolled plate width is minimum,and the average grain size is minimum owing to the relatively complete recrystallization.展开更多
Gradient microstructure modification is a cost-efficient strategy for high strength without compromising ductility,which is urgently needed in the fundamental science of engineering materials.In this study,heterogeneo...Gradient microstructure modification is a cost-efficient strategy for high strength without compromising ductility,which is urgently needed in the fundamental science of engineering materials.In this study,heterogeneous structures of AZ61 alloy bars with anisotropic gradients(with different grain size distributions from the surface to the center)were observed to exhibit strong strength-ductility synergies under different deformation tem peratures.The results reveal that the grain refinement process under mediumlow temperature deformation conditions(≤350℃)consists of four transition stages along the radial direction,i.e.,twin activations and deformation band formations,dislocation cells and pile-ups,ultrafine sub-grains,and randomly orientated quasi-micron grains.Different deformation temperatures have a great influence on twin activations and deformation band formations,and the high temperature can easily provoke the initiation of non-basal slip.The deformation bands were determined as a primary nucleation site due to their highly unstable dislocation hindrance ability.Analysis in combination with the Radial forging(RF)deformation process,the differences of dynamic precipitates can be attributed to microstructural difference and solubility limit of Al at different tem peratures.By summarizing the tensile test results,the sample forged at 350℃exhibited the best strength-ductility synergy,exhibiting the highest elongation(EL)of 23.2%with a 251 MPa yield strength(YS)and 394 MPa ultimate tensile strength(UTS)in center region,and combined with the highest strength value of 256 MPa YS and 420 MPa UTS in the center region,while the EL was slightly degraded to 19.8%.展开更多
Flexible electronics have emerged as an exciting research area in recent years,serving as ideal interfaces bridging biological systems and conventional electronic devices.Flexible electronics can not only collect phys...Flexible electronics have emerged as an exciting research area in recent years,serving as ideal interfaces bridging biological systems and conventional electronic devices.Flexible electronics can not only collect physiological signals for human health monitoring but also enrich our daily life with multifunctional smart materials and devices.Conductive hydrogels(CHs)have become promising candidates for the fabrication of flexible electronics owing to their biocompatibility,adjustable mechanical flexibility,good conductivity,and multiple stimuli-responsive properties.To achieve on-demand mechanical properties such as stretchability,compressibility,and elasticity,the rational design of polymer networks via modulating chemical and physical intermolecular interactions is required.Moreover,the type of conductive components(eg,electron-conductive materials,ions)and the incorporation method also play an important role in the conductivity of CHs.Electron-CHs usually possess excellent conductivity,while ion-CHs are generally transparent and can generate ion gradients within the hydrogel matrices.This mini review focuses on the recent advances in the design of CHs,introducing various design strategies for electron-CHs and ion-CHs employed in flexible electronics and highlighting their versatile applications such as biosensors,batteries,supercapacitors,nanogenerators,actuators,touch panels,and displays.展开更多
Radial forging(RF)is an economical manufacturing forging process,in which four dies arranged radially around the workpiece simultaneously act on the workpiece with high-frequency radial movement.In this study,a ZK60 m...Radial forging(RF)is an economical manufacturing forging process,in which four dies arranged radially around the workpiece simultaneously act on the workpiece with high-frequency radial movement.In this study,a ZK60 magnesium alloy step-shaft bar was processed under different accumulated strains by RF at350℃.The deformation behavior,microstructure evolution,and mechanical responses of this bar were systematically investigated via numerical simulations and experiments.At the early deformation stage of forging,the material undergoes pronounced grain refinement but an inhomogeneous grain structure is formed due to the strain gradient along the radial direction.The grains in different radial parts were gradually refined by increasing the RF pass,resulting in a bimodal grained structure comprising coarse(~14.1μm)and fine(~2.3μm)grains.With the RF pass increased,the initial micro-sizeβ-phases were gradually crushed and dissolved into the matrix mostly,eventually evolving to form a higher area fraction of nano-sized Zn2 Zr spheroidal particles uniformly distributed through the grain interior.The texture changed as the RF strain increased,with the c-axes of most of the deformed grains rotating in the RD.Additionally,excellent mechanical properties including higher values of tensile strengths and ductility were attained after the three RFed passes,compared to the as-received sample.展开更多
As the process parameters of pilger cold-rolled seamless steel tubes are basically based on experience leading to the generation of defects, 304 stainless steel was chosen and the important process parameters includin...As the process parameters of pilger cold-rolled seamless steel tubes are basically based on experience leading to the generation of defects, 304 stainless steel was chosen and the important process parameters including the feed, rotation angle and Q value (the ratio of the length of the deformation section to that of the finishing section) were selected to analyze the effect of different process parameters on the tube forming process and rules. The results show that during the cold rolling process, the rolling force, the equivalent stress of the tube, the residual stress and the springback of the external diameter increased with the increase in the feed rate and the rotation angle and the decrease in Q value. Increasing the feed quantity and decreasing Q value will lead to the decrement in the roundness of the pipe. After comprehensive evaluation of the advantages and disadvantages, a set of optimal parameters are selected to carry out the experiment. The residual stress and the outer diameter of the finished products were measured. The results of the measurement and the numerical simulation results are within reasonable range, and the accuracy of the numerical simulations and the influence of the process parameters on the pilger cold rolling are further verified.展开更多
基金National Natural Science Foundation of China(Grant No.U1510131)Key Research and Development Projects of Shanxi Province of China(Grant Nos.201603D121010,201603D111004)+3 种基金Science and Technology Project of Jin Cheng City of China(Grant No.20155010)Youth Program of National Natural Science Fund of China(Grant No.51604181)Project of Young Scholar of Shanxi ProvinceLeading Talent Project of Innovative Entrepreneurial Team of Jiangsu Province(Grant No.51501122)
文摘Currently, when magnesium alloy sheet is rolled, the method of controlling roll temperature is simple and inaccurate. Furthermore, roll temperature has a large influence on the quality of magnesium alloy sheet; therefore, a new model using circular fluid flow control roll temperature has been designed. A fluid heat transfer structure was designed, the heat transfer process model of the fluid heating roll was simplified, and the finite di erence method was used to cal?culate the heat transfer process. Fluent software was used to simulate the fluid?solid coupling heat transfer, and both the trend and regularity of the temperature field in the heat transfer process were identified. The results show that the heating e ciency was much higher than traditional heating methods(when the fluid heat of the roll and tempera?ture distribution of the roll surface was more uniform). Moreover, there was a bigger temperature di erence between the input and the output, and after using reverse flow the temperature di erence decreased. The axial and circum?ferential temperature distributions along the sheet were uniform. Both theoretical calculation results and numerical simulation results of the heat transfer between fluid and roll were compared. The error was 1.8%–12.3%, showing that the theoretical model can both forecast and regulate the temperature of the roll(for magnesium alloy sheets) in the rolling process.
基金the National Natural Science Foundation of China(No.51905366,51901149,51671041,51604181,U1910213 and U1610253)the Key Research and Development Program of Shanxi Province(No.201603D111004)+1 种基金the Fund for Shanxi“1331 Project”Key Subjects Construction,Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2019L0632)Taiyuan University of Science and Technology Scientific Research Initial Funding(20182030,20192003 and 20192008)。
文摘In this study,accumulated extrusion bonding(AEB)process with application of artificial water cooling was successfully performed to fabricate fined-grains AZ31B Mg alloy sheets at 150℃,200℃ and 250℃.The resultant microstructure and mechanical properties are systematically investigated.It reveals that the processing temperature has an important effect on the microstructural evolution during extrusion.During AEB process at 150℃ and 200℃,{10-12}tensile twinning was activated at early stage of extrusion,and subsequently continuous dynamic recrystallization(CDRX)occurred and dominated the further deformation.However,for the sample extruded at 250℃,hardly any twins can be observed,and new fined dynamic recrystallized grains were found along grain boundaries.Artificial cooling was utilized to reduce the rate of grain growth out of the extrusion die,resulting the grains significantly refined from 11μm to 2.5μm.Local high dislocation density region was also observed in the microstructure of sample processed at 150℃ in artificial cooling condition,and the degree decreased with the processing temperature increase.The results summarized from tensile tests indicated that due to the grain refinement the strength and ductility was significantly enhanced(YS of 186 MPa vs.145 MPa,UTS of 391 MPa vs.336 MPa and FE of 31.5%vs.24.5%compared with the as-received sample).Subsequently,annealing treatment at different temperatures was applied to eliminate the high dislocation density.The sample annealed at 200℃ exhibited the best comprehensive mechanical property with YS of 179 MPa,UTS of 390 MPa and FE of 33.0%.As the annealing temperature increasing,the dislocation density was reduced by static recrystallization(SRX)and grain growth,leading to a decreased strength and ductility.
基金This work is financially supported by the National Key Research and Development Program of China(2016YFB0301104)the National Natural Science Foundation of China(51771043).
文摘Temperature detection and tracking of AZ31B magnesium alloy plate during the air-cooling transport process were investigated and carried out under different thicknesses and initial temperatures.Experimental results show that there exists a sudden temperature drop in the range of 1/4 of width distanced from the edge.When the plate is cooled by 25-56°C,the maximum inhomogeneous temperature distribution under all process conditions will appear in width direction.For the air-cooling transport process,the temperature control model for predicting the average temperature of the Mg plate after a predetermined time period can be established by modifying the Stefan-Boltzmann empirical equation.The model mainly depends on the plate specifications and air-cooling time.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB722801)the Postdoctoral Science Foundation of China(Grant No.2015M571285)+3 种基金the National Natural Science Foundation of China(Grant No.51401140)the Postdoctoral Research Station Foundation of Taiyuan University of Science and Technology,China(Grant Nos.20142014,20152041,and 20151082)the Natural Science Foundation of Shanxi Province,China(Grants Nos.2015021019,2015091011,and 2015081011)the Key Team of Scientific and Technological Innovation of Shanxi Province,China(Grant No.2013131009)
文摘Highly textured Heusler alloy Mn_(46)Ni_(42)Sn_(11)Sb_1 ribbons were prepared by melt spinning. The annealed high Mn content Mn46Ni42Sn11Sb1 ribbon cross-section microstructure, crystal structure, martensitic transformation(MT), and magnetoresistance(MR) properties were investigated. The MR in the annealed ribbon was assessed by the magnetic field direction perpendicular to the ribbon surface with the magnetic field up to 30 k Oe. The large negative value of 25% for MR was obtained at 244 K. The exchange bias(EB) effects of the as-spun and annealed ribbons were investigated. After annealing, the EB effects have been improved by about 25 Oe at the temperature of 50 K. The magnetizations have increased approximately by 10% more than the as-spun ribbon.
基金supported by the Natural Science Foundation of Shanxi Province,China(Grant No.2010011032-1)the Specialized Research Fund for Doctoral Scientific Research of Ministry of Education of China(Grant No.201014151110003)+5 种基金the Doctoral Scientific Research Foundation of Taiyuan University of Science and Technology,China(Grant No.20122036)the Postdoctoral Research Station Foundation of Taiyuan University of Science and Technology,Chinathe Research Project Supported by Shanxi Scholarship Council,China(Grant No.2013-098)the Graduate Student Innovation Project of Shanxi Province,China(Grant No.20133114)the National Natural Science Foundation of China(Grant No.51375325)the National Key Basic Research Program of China(Grant No.2012CB722801)
文摘The crystal structure, phase transition, and magnetocaloric effect in Ni42.8Mn40.3Co5.7Sn11.2alloy are investigated by structure analysis and magnetic measurements. A large magnetic entropy change of 45.6 J/kg·K is obtained at 215 K under a magnetic field of 30 kOe(1 Oe = 79.5775 A·m-1). The effective refrigerant capacity of Ni42.8Mn40.3Co5.7Sn11.2alloy reaches 72.1 J/kg under an applied field changing from 0 to 30 kOe. The external magnetic field shifts the martensitic transition temperature about 3–4 K/10 kOe towards low temperature, indicating that magnetic field can retard the phase transition to a certain extent. The origin of large magnetic entropy change is discussed in the paper.
基金Supported by National Natural Science Foundation of China(Grant Nos.U1910213,U1610253,51604181)Shanxi Provincial Key Research and Development Program of China(Grant Nos.201603D111004,201803D121026).
文摘A decrease in the weight of aerospace vehicles,large ships,weapons,and high-speed trains will increase the demand for wide-width magnesium alloy plates and their composite parts to replace steel and plastic.An investigation was conducted to study the variation in deformation behaviors along the transverse direction during the warm rolling of a 1480-mm-wide AZ31B plate.A uniaxial thermal compression test with a 59%reduction was performed at different positions on a 13.7-mm-thick rolled plate along the width direction at a temperature of 220℃ and 270℃ and strain rate of 15 s^(−1).At the same time,the 13.7-mm-thick plate was rolled in a single pass to 5.6 mm on a mill with a 1725-mm-wide roll to confirm the thermal deformation behavior and the dynamic recrystallization(DRX).The results show that the main texture type does not change and the grain size does not have a clear deflection when the magnesium alloy plate reaches a certain value under rolling accumulative reduction.The grain size of a 13.7-mm-thick plate increases with a decrease in the distance to the center layer in the thickness direction.In the width direction,the edge(R6)first decreases and then increases toward the symmetric plane(R1).The critical stress required for dynamic recrystallization in the transition zone R3 of the rolled plate width is minimum,and the average grain size is minimum owing to the relatively complete recrystallization.
基金the financial support of the National Natural Science Foundation of China(Nos.U1910213 and 52205400)the China Postdoctoral Science Foundation(No.2021M692626)+1 种基金the Fundamental Research Program of Shanxi Province(No.202203021212321),Technological Innovation Talent Team Special Plan of Shanxi Province(No.202204051002002)the Doctoral Starting up Foundation of Taiyuan University of Science and Technology(No.20222046).
文摘Gradient microstructure modification is a cost-efficient strategy for high strength without compromising ductility,which is urgently needed in the fundamental science of engineering materials.In this study,heterogeneous structures of AZ61 alloy bars with anisotropic gradients(with different grain size distributions from the surface to the center)were observed to exhibit strong strength-ductility synergies under different deformation tem peratures.The results reveal that the grain refinement process under mediumlow temperature deformation conditions(≤350℃)consists of four transition stages along the radial direction,i.e.,twin activations and deformation band formations,dislocation cells and pile-ups,ultrafine sub-grains,and randomly orientated quasi-micron grains.Different deformation temperatures have a great influence on twin activations and deformation band formations,and the high temperature can easily provoke the initiation of non-basal slip.The deformation bands were determined as a primary nucleation site due to their highly unstable dislocation hindrance ability.Analysis in combination with the Radial forging(RF)deformation process,the differences of dynamic precipitates can be attributed to microstructural difference and solubility limit of Al at different tem peratures.By summarizing the tensile test results,the sample forged at 350℃exhibited the best strength-ductility synergy,exhibiting the highest elongation(EL)of 23.2%with a 251 MPa yield strength(YS)and 394 MPa ultimate tensile strength(UTS)in center region,and combined with the highest strength value of 256 MPa YS and 420 MPa UTS in the center region,while the EL was slightly degraded to 19.8%.
基金support from the Natural Sciences and Engineering Research Council of Canada(NSERC)the Canada Foundation for Innovation(CFI),and the Canada Research Chairs Program(H.Zeng).
文摘Flexible electronics have emerged as an exciting research area in recent years,serving as ideal interfaces bridging biological systems and conventional electronic devices.Flexible electronics can not only collect physiological signals for human health monitoring but also enrich our daily life with multifunctional smart materials and devices.Conductive hydrogels(CHs)have become promising candidates for the fabrication of flexible electronics owing to their biocompatibility,adjustable mechanical flexibility,good conductivity,and multiple stimuli-responsive properties.To achieve on-demand mechanical properties such as stretchability,compressibility,and elasticity,the rational design of polymer networks via modulating chemical and physical intermolecular interactions is required.Moreover,the type of conductive components(eg,electron-conductive materials,ions)and the incorporation method also play an important role in the conductivity of CHs.Electron-CHs usually possess excellent conductivity,while ion-CHs are generally transparent and can generate ion gradients within the hydrogel matrices.This mini review focuses on the recent advances in the design of CHs,introducing various design strategies for electron-CHs and ion-CHs employed in flexible electronics and highlighting their versatile applications such as biosensors,batteries,supercapacitors,nanogenerators,actuators,touch panels,and displays.
基金the financial support of the National Natural Science Foundation of China(Nos.U1910213 and U1610253)the Key Research and Development Program of Shanxi Province(Nos.201603D111004,201803D121026 and 201903D121088)+1 种基金the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2019L0614)the Taiyuan University of Science and Technology Scientific Research Initial Funding(TYUST SRIF)(No.20192002)。
文摘Radial forging(RF)is an economical manufacturing forging process,in which four dies arranged radially around the workpiece simultaneously act on the workpiece with high-frequency radial movement.In this study,a ZK60 magnesium alloy step-shaft bar was processed under different accumulated strains by RF at350℃.The deformation behavior,microstructure evolution,and mechanical responses of this bar were systematically investigated via numerical simulations and experiments.At the early deformation stage of forging,the material undergoes pronounced grain refinement but an inhomogeneous grain structure is formed due to the strain gradient along the radial direction.The grains in different radial parts were gradually refined by increasing the RF pass,resulting in a bimodal grained structure comprising coarse(~14.1μm)and fine(~2.3μm)grains.With the RF pass increased,the initial micro-sizeβ-phases were gradually crushed and dissolved into the matrix mostly,eventually evolving to form a higher area fraction of nano-sized Zn2 Zr spheroidal particles uniformly distributed through the grain interior.The texture changed as the RF strain increased,with the c-axes of most of the deformed grains rotating in the RD.Additionally,excellent mechanical properties including higher values of tensile strengths and ductility were attained after the three RFed passes,compared to the as-received sample.
基金The authors are grateful for the financial assis- tance from the National Science Foundation of China (U1710113), the China Postdoctoral Science Foundation (2017M622903), the Fund for Shanxi Key Subjects Construction, Excellent innovation projects of graduate students in Shanxi (2017SY077), Heavy Machinery Engineering Research Center of Ministry of Education (20172004).
基金This work was supported by the National Natural Science Foundation of China (No. U1510131) and the Applied Basic Research Project of Shanxi Province (Nos. 201701D121078 and 201701D221143).
基金the National Natural Science Foundation of China(Grant No.U1710113)the China Postdoctoral Science Foundation(Grant No.2017M622903)+2 种基金the National Key Research and Development Program of Shanxi Province(Grant No.201703D121008)the Project of Excellent Graduate Innovation in Shanxi(Grant No.2017SY077)the Graduate Innovation Funding Scheme for Heavy Machinery”(Grant Nos.20172001 and 20172004)for financial support and authorization to publish this work.
文摘As the process parameters of pilger cold-rolled seamless steel tubes are basically based on experience leading to the generation of defects, 304 stainless steel was chosen and the important process parameters including the feed, rotation angle and Q value (the ratio of the length of the deformation section to that of the finishing section) were selected to analyze the effect of different process parameters on the tube forming process and rules. The results show that during the cold rolling process, the rolling force, the equivalent stress of the tube, the residual stress and the springback of the external diameter increased with the increase in the feed rate and the rotation angle and the decrease in Q value. Increasing the feed quantity and decreasing Q value will lead to the decrement in the roundness of the pipe. After comprehensive evaluation of the advantages and disadvantages, a set of optimal parameters are selected to carry out the experiment. The residual stress and the outer diameter of the finished products were measured. The results of the measurement and the numerical simulation results are within reasonable range, and the accuracy of the numerical simulations and the influence of the process parameters on the pilger cold rolling are further verified.