In order to investigate the effects of pockets in the porthole die on the metal flow,temperature at the die bearing exit and the extrusion load were contrasted with the traditional die design without the pockets in th...In order to investigate the effects of pockets in the porthole die on the metal flow,temperature at the die bearing exit and the extrusion load were contrasted with the traditional die design without the pockets in the lower die.Two different multi-hole porthole dies with and without pockets in lower die were designed.And the extrusion process was simulated based on the commercial software DEFORM-3D.The simulation results show that the pockets could be used to effectively adjust the metal flow and especially benefit to the metal flow under the legs.In addition,the maximum temperature at the die bearing and the peak extrusion load decrease,which indicates the possibility of increasing the extrusion speed and productivity.展开更多
The effects of die structure such as the height of the welding,the welding angle and chamber the shape of the bridge on the welding quality of profiles were investigated by means of the commercial software DEFORM-3D.T...The effects of die structure such as the height of the welding,the welding angle and chamber the shape of the bridge on the welding quality of profiles were investigated by means of the commercial software DEFORM-3D.The numerical simulation results show that the welding quality of the hollow profiles has great sensitive to the die structure.With increasing the welding chamber height and decreasing the welding angle of the die leg can improve the welding quality.In addition,the welding quality index k of the new designed shape of the die leg is little down from 4.1 to 3.9 comparing the standard leg.展开更多
Semi-solid casting of M2 high speed steel ingots was investigated by inclined slope pre-crystallization method. Effects of casting temperature and slope length on the microstructure of M2 HSS ingots were investigated....Semi-solid casting of M2 high speed steel ingots was investigated by inclined slope pre-crystallization method. Effects of casting temperature and slope length on the microstructure of M2 HSS ingots were investigated. M2 cast ingots of non-dendritic primary austenite and fine eutectic ledeburite network carbide structure were obtained, with the casting temperature, slope length and angle of 1480 ℃, 500 mm and 60° respectively. Meanwhile, the microstructure of cast samples was quantitatively assessed by Image tool software. Results show that optimum mean equivalent diameter of primary austenite crystal grain is 50.8 μm, shape factor is 0.83, and mean thickness of network carbide is 5.21 μm.展开更多
According to the rigid-viscoplasticity finite element method,the porthole die extrusion process of an aluminum harmonica-shaped tube was successfully simulated based on software Deform-3D. The distribution of stress f...According to the rigid-viscoplasticity finite element method,the porthole die extrusion process of an aluminum harmonica-shaped tube was successfully simulated based on software Deform-3D. The distribution of stress field,effective strain field,velocity field and temperature field during the extrusion process were discussed and the metal flow in welding extrusion was analyzed. The simulation results show that the material flow velocities in the bearing exit are non-uniform with the originally designed die and the forepart of the profile is not neat or even. Aiming at solving this problem,the modification method of die structure was improved. The result shows that the uniform material flow velocities in the die exit and a perfect extruded are obtained by modification bearing length.展开更多
基金Project(2007BAE38B00) supported by the National Key Technology R&D Program in the 11th Five Year Plan of China
文摘In order to investigate the effects of pockets in the porthole die on the metal flow,temperature at the die bearing exit and the extrusion load were contrasted with the traditional die design without the pockets in the lower die.Two different multi-hole porthole dies with and without pockets in lower die were designed.And the extrusion process was simulated based on the commercial software DEFORM-3D.The simulation results show that the pockets could be used to effectively adjust the metal flow and especially benefit to the metal flow under the legs.In addition,the maximum temperature at the die bearing and the peak extrusion load decrease,which indicates the possibility of increasing the extrusion speed and productivity.
基金Founded by the National Key Technology R&D Program in the 11th Five Year Plan of China(2007BAE38B00)
文摘The effects of die structure such as the height of the welding,the welding angle and chamber the shape of the bridge on the welding quality of profiles were investigated by means of the commercial software DEFORM-3D.The numerical simulation results show that the welding quality of the hollow profiles has great sensitive to the die structure.With increasing the welding chamber height and decreasing the welding angle of the die leg can improve the welding quality.In addition,the welding quality index k of the new designed shape of the die leg is little down from 4.1 to 3.9 comparing the standard leg.
基金Funded by the Science Foundation of Beijing Jiaotong University (No.230-12)
文摘Semi-solid casting of M2 high speed steel ingots was investigated by inclined slope pre-crystallization method. Effects of casting temperature and slope length on the microstructure of M2 HSS ingots were investigated. M2 cast ingots of non-dendritic primary austenite and fine eutectic ledeburite network carbide structure were obtained, with the casting temperature, slope length and angle of 1480 ℃, 500 mm and 60° respectively. Meanwhile, the microstructure of cast samples was quantitatively assessed by Image tool software. Results show that optimum mean equivalent diameter of primary austenite crystal grain is 50.8 μm, shape factor is 0.83, and mean thickness of network carbide is 5.21 μm.
基金Project(50674017) supported by the National Natural Science Foundation of China
文摘According to the rigid-viscoplasticity finite element method,the porthole die extrusion process of an aluminum harmonica-shaped tube was successfully simulated based on software Deform-3D. The distribution of stress field,effective strain field,velocity field and temperature field during the extrusion process were discussed and the metal flow in welding extrusion was analyzed. The simulation results show that the material flow velocities in the bearing exit are non-uniform with the originally designed die and the forepart of the profile is not neat or even. Aiming at solving this problem,the modification method of die structure was improved. The result shows that the uniform material flow velocities in the die exit and a perfect extruded are obtained by modification bearing length.
