汽车大型铝合金覆盖件的充液成形技术

铝合金覆盖件的应用是汽车轻量化的关键,但其制造难度较大。通过研究铝合金发动机罩外板的充液成形工艺过程,了解先进柔性技术在汽车领域应用的可行性。分析了工艺参数中液室压力与凸模行程匹配及压边力对板料减薄率的影响,从成形极限上判断零件无起皱、破裂现象的范围。获得最优的整形液室压力为12～20 MPa,压边力过小,板料不能充分塑性变形,压边力过大,板料易失稳破裂,最优的恒定压边力范围为1600～2000 k N。研究表明,采用板材充液成形柔性制造工艺,可降低噪音,无冲击线,且由于液室压力的作用,滑移线减小,可提高大型铝合金弱刚度板材的质量。

Hydroforming technology for large aluminum alloy panel of automobile

The lightweight of automobile is the key of the application of aluminum alloy panel, but it is difficult to manufacture.The advanced flexible technology is feasible in the application of automotive field by researching the hydroforming process of the aluminum alloy engine hood outer panel.Then, the influences of matching chamber pressure with punch stroke and the blank holder force in the technological parameters on the thinning rate of sheet metal were analyzed, and the scope of the part without wrinkling and rupture was determined by the forming limit diagram (FLD).Furthermore, the optimal shaping chamber pressure is obtained within 12-20 MPa.However, when the blank holder force is too small, the plastic deformation of sheet metal can not be realized completely;while the blank holder force is too large, the rupture is easily occurred.Thus, the optimal constant blank holder force is within 1600-2000 kN.The results show that the noise is reduced in the factory by the sheet hydroforming of flexible manufacturing process, and there is no impact line.Finally, the slip line is reduced because of chamber pressure, and the quality of large aluminum alloy plate with weak rigidity is improved.