6082铝合金上摆臂件成形工艺初探

Preliminary study on forming process of upper swing arm for 6082 aluminum alloy

针对6082铝合金热锻时形成粗晶并影响锻件性能的问题,通过对坯料进行加热保温,对未变形与变形条件下的晶粒粗化进行研究,定量分析坯料表面粗晶层厚度,探讨加热温度与保温时间、热变形条件对6082铝合金粗晶现象的影响规律。得出结论:保温时间超过25 min后,粗晶层会迅速扩大;同时,在变形量为0. 7、变形温度为350~500℃区间、变形速率为0. 1~5 s-1条件下对试样进行压缩,并利用EBSD图像观察晶粒尺寸,发现均存在混晶现象,大应变速率下采用高变形温度有利于改善混晶。在此基础上,初步制定3种汽车上摆臂件的成形工艺方案,发现加热至540℃预锻并经二次加热再终锻这一方案有利于减小锻件粗晶层厚度。

For the problem of formation of coarse grains in hot forging and affecting the properties of 6082 aluminum alloy forgings,the grain coarsening tests under undeformed and deformed conditions were implemented by heating and holding for blank.Then,the thickness of coarse grain layer on the surface of blank was quantitatively analyzed,and the influences of heating temperature,holding time and thermal deformation conditions on coarse grain phenomenon of 6082 aluminum alloy were discussed.The results show that the coarse grain layer expands rapidly when the holding time exceeds 25 minutes.Under the deformation of 0.7,deformation temperature of 350-450℃and the deformation rate of 0.1-5 s-1,the sample was compressed,and the grain size was observed by EBSD image.It is found that there are mixed crystals,and the high deformation temperature at large strain rate is beneficial to weaken the mixed crystals.According to the conclusion,three forming process schemes of automobile upper swing arm were initially worked out,and the scheme of heating the material to 540℃for pre-forging and reheating to the same temperature for finish-forging is more reasonable to reduce the thickness of coarse grain layer of forgings.