The hot forging of large-scale P/M TiAl alloy billet deformation was investigated based on a joint application of Deform-3D-based numerical simulation and physical simulation techniques.The temperature dependence on t...The hot forging of large-scale P/M TiAl alloy billet deformation was investigated based on a joint application of Deform-3D-based numerical simulation and physical simulation techniques.The temperature dependence on the thermal and mechanical properties of the billet was considered and the optimum hot working temperature of packed TiAl alloy was 1150-1200 °C.Based on the simulation,the material flow and thermo mechanical field variables,such as stress,strain,and temperature distribution were obtained and the relationships of load—displacement and load—time were figured out.To verify the validity of the simulation results,the experiments were also carried out in a forging plant,and a pancake with diameter of 150 mm was obtained exhibiting a regular shape.展开更多
To investigate the effects of billet geometry on the cold precision forging process of a helical gear, six different billet geometries were designed utilizing the relief-hole principle. And the influences of the bille...To investigate the effects of billet geometry on the cold precision forging process of a helical gear, six different billet geometries were designed utilizing the relief-hole principle. And the influences of the billet geometry on the forming load and the deformation uniformity were analyzed by three-dimensional （3D） finite element method （FEM） under the commercial software DEFORM 3D. The billet geometry was optimized to meet lower forming load and better deformation uniformity requirement. Deformation mechanism was studied through the distribution of flow velocity field and effective strain field. The forging experiments of the helical gear were successfully performed using lead material as a model material under the same process conditions used in the FE simulations. The results show that the forming load decreases as the diameter of relief-hole do increases, but the effect of do on the deformation uniformity is very complicated. The forming load is lower and the deformation is more uniform when do is 10 mm.展开更多
Sand casting and die casting processes have been used widely for complex automotive products such as knuckle, arm, etc.Usually, a part fabricated by casting has limited strength due to manufacturing defects such as th...Sand casting and die casting processes have been used widely for complex automotive products such as knuckle, arm, etc.Usually, a part fabricated by casting has limited strength due to manufacturing defects such as the dendrite structure, segregation and porosities.As an attempt to offer a solution to these problems, forging has been used as an alternative process.However, the forging process provides limited formability for complex shape products.Rheo-forging of metal offers not only superior mechanical strength but also requires significantly lower machine loads than solid forming processes.In order to produce semi-solid materials of the desired microstructure, a stirring process is applied during solidification of molten metal.The results of an A356 aluminum alloy sample, which are obtained by experiment and by simulation using DEFORM 3D, are present.展开更多
In this paper,45#steel supports prepared by liquid forging showed excellent performances and the effects of processing techniques on the development of microstructures and mechanical properties of these steel supports...In this paper,45#steel supports prepared by liquid forging showed excellent performances and the effects of processing techniques on the development of microstructures and mechanical properties of these steel supports were researched.The liquid forging process was simulated and technological parameters were optimized via a Pro CAST simulation software.The solidification time,temperature distribution,first principal stress distribution of the 45#steel supports varied with time,temperatures,and position.Two principal parameters,pouring temperature and dwell time,were assessed for their effects on microstructures,mechanical properties,and wear resistance properties of 45#steel supports.Results showed that the optimal pouring temperature of the molten metal and the pressure-holding time were between 1540℃ and 1560℃ and between 35 s and 40 s,respectively.The microstructure,mechanical properties,and fracture behavior of different positions in the support were also discussed,and the central position performed better than the edge because of plastic deformation.Finally,the dynamic solidification process was also investigated and the liquid forging process of 45#steel supports was complex and contained some special metal liquid convection and several plastic deformation stages.展开更多
基金Project (2011CB605505) supported by the National Basic Research Program of ChinaProject (2011QNZT041) supported by the freedom explore Program of Central South University,ChinaProject (84088) supported by the and Postdoctoral Foundation Supported Project of Central South University,China
文摘The hot forging of large-scale P/M TiAl alloy billet deformation was investigated based on a joint application of Deform-3D-based numerical simulation and physical simulation techniques.The temperature dependence on the thermal and mechanical properties of the billet was considered and the optimum hot working temperature of packed TiAl alloy was 1150-1200 °C.Based on the simulation,the material flow and thermo mechanical field variables,such as stress,strain,and temperature distribution were obtained and the relationships of load—displacement and load—time were figured out.To verify the validity of the simulation results,the experiments were also carried out in a forging plant,and a pancake with diameter of 150 mm was obtained exhibiting a regular shape.
基金Project(51105287)supported by the National Natural Science Foundation of China
文摘To investigate the effects of billet geometry on the cold precision forging process of a helical gear, six different billet geometries were designed utilizing the relief-hole principle. And the influences of the billet geometry on the forming load and the deformation uniformity were analyzed by three-dimensional （3D） finite element method （FEM） under the commercial software DEFORM 3D. The billet geometry was optimized to meet lower forming load and better deformation uniformity requirement. Deformation mechanism was studied through the distribution of flow velocity field and effective strain field. The forging experiments of the helical gear were successfully performed using lead material as a model material under the same process conditions used in the FE simulations. The results show that the forming load decreases as the diameter of relief-hole do increases, but the effect of do on the deformation uniformity is very complicated. The forming load is lower and the deformation is more uniform when do is 10 mm.
基金Project(2009-0081077) supported by the National Research Foundation (NRF) by Korea Government
文摘Sand casting and die casting processes have been used widely for complex automotive products such as knuckle, arm, etc.Usually, a part fabricated by casting has limited strength due to manufacturing defects such as the dendrite structure, segregation and porosities.As an attempt to offer a solution to these problems, forging has been used as an alternative process.However, the forging process provides limited formability for complex shape products.Rheo-forging of metal offers not only superior mechanical strength but also requires significantly lower machine loads than solid forming processes.In order to produce semi-solid materials of the desired microstructure, a stirring process is applied during solidification of molten metal.The results of an A356 aluminum alloy sample, which are obtained by experiment and by simulation using DEFORM 3D, are present.
基金Project supported by the International Cooperation Project of the Ministry of Science and Technology of China(No.2014DFR50320)the National Natural Science Foundation of China(No.51174064)。
文摘In this paper,45#steel supports prepared by liquid forging showed excellent performances and the effects of processing techniques on the development of microstructures and mechanical properties of these steel supports were researched.The liquid forging process was simulated and technological parameters were optimized via a Pro CAST simulation software.The solidification time,temperature distribution,first principal stress distribution of the 45#steel supports varied with time,temperatures,and position.Two principal parameters,pouring temperature and dwell time,were assessed for their effects on microstructures,mechanical properties,and wear resistance properties of 45#steel supports.Results showed that the optimal pouring temperature of the molten metal and the pressure-holding time were between 1540℃ and 1560℃ and between 35 s and 40 s,respectively.The microstructure,mechanical properties,and fracture behavior of different positions in the support were also discussed,and the central position performed better than the edge because of plastic deformation.Finally,the dynamic solidification process was also investigated and the liquid forging process of 45#steel supports was complex and contained some special metal liquid convection and several plastic deformation stages.
