Translated Abstract
ABSTRACTWith the development of automobile industry, the demand of high performance aluminum alloy wheel hub increases gradually, the structure design and forming technology also constantly be improved. Although the traditional wheel hub casting process have been improved, the internal organization and mechanics performance of the casting wheel hub have been improved limitedly. The aluminum alloy wheel hub formed by forging process have the advantages of good performance, high quality and light weight, but it is not widely applied as the complex forging process and high manufacturing cost. The performance of the wheel hub could approach the forging workpiece with the casting & forging process that based on the liquid die forging technology and continuous casting & rolling technology under the condition of low investment and simple process. But the performance of the wheel hub’s rim improved limitedly, so it needs a new technology to form whole wheel hub with good performance under low cost.A kind of integration forming process combining casting & forging and spinning called integration lightweight forming process of casting, forging and spinning is proposed in this paper. In the new process, the wheel hub blank with good performance and high precision for spinning formed by the casting & forging process, then the rim of the wheel hub is formed by the spinning process, so the whole wheel hub with good performance is got.With the topology optimization technology as theoretical basis, the lightweight research on existing hub structure has done via finite element analysis technology. The new designed structure was 10% lighter than anterior in the premise of meeting the performance requirements, and material performance has been further effective applied.The new casting & forging mold has designed according to the new process and new hub structure’s request, with reasonable overflow-vent system and side core-pulling system. The floating mold is adopted in the forging system, making the forging punch cover the whole wheel except rim part.The forging process during casting & forging process of aluminum alloy wheel hub was focused studied by the finite element simulation technology on the basis of metal forming theory. The finite element models of wheel hub was set up, the influence of mold tempreture on the process is studied, the change of work-piece temperature field after filling was analyzed, the position of defects after casting was predicted, the influence of die temperature on the casting & forging process is researched, the suitable forging time and the law of forging force changed with die temperature is obtained. The influence of the piston bottom pressure on the process is investigated too, the results show that when the piston pressure increases in the proper range, the pressure on work-piece is increased significantly, and the performance of the work-piece is improved. Finally, as to the property of the wheel rim improved limitedly after forging process, spinning process simulation of the wheel rim is put forward, form which the property of the rim could be promoted. So the good performance of the whole aluminum alloy wheel hub has been got. All the results provide the technical basis for the whole forming simulation procedure of the aluminum alloy automobile wheel hub.The wheel hub samples formed by the casting & forging process are analyzed by the method of combining metallographic test and finite element simulation.The results show that the microstructure in the forging area is uniform and compact, which indicate that the casting organization in forging area has been improved by the follow forging process. So the reliability of the process is verified.
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