一种孤立性铝箔针孔的特征及其形成机制

为减少生产过程中典型孤立形态针孔的形成，通过光学显微镜、扫描电镜等测试手段对铝箔中孤立类针孔的微观形貌进行观察，并对其形成机制进行探讨，采用光学显微镜标尺统计法测量油坑面积，利用Ansys有限元进行模拟分析。结果表明:孤立性针孔四周围绕着凹陷，铝箔光面分布着小的油坑，粗糙面分布着小的凹坑, 此类针孔在初次轧制道次后有一定的方向性，其长度方向和铝箔轧制走向一致，此类孤立性针孔不存在外来杂质；轧制过程中，在油坑底部分布着最大等效应力；在双向轧制张力作用下，光面油坑和毛面凹坑相连的部位强度最为薄弱，此处铝箔最容易被撕裂，导致铝箔的连续性遭到破坏，形成了此类孤立性针孔；针孔面积比随着轧制道次的增加逐渐减小，随着轧制速度的增大而增大。因此，在生产过程中可通过适当减少毛面粗糙度、控制光面轧制油坑比率等有效措施控制针孔形成。

Discussion on the Characteristics of the Isolated Aluminum Foil Pinhole Defect and Its Formation Mechanism

In this paper, we investigated the micro-morphology of the isolated aluminum foil pinhole by using metallographic microscopes and SEM. The pinhole formation mechanism has been discussed. The oil pit area was measured by optical microscope scale statistics. Ansys finite element simulation analysis. The results show that, it is subsequently demonstrated that, the isolated aluminum foil pinhole is often tends to be encircled by the pit, and the little oil pits randomly distributed over the smooth surface of the foil, and some little pits in the matte surface too. After initial rolling pass, the direction of these pinhole are consistent with the rolling direction. SEM analysis of the pinhole micro regions indicates that the isolated aluminum foil pinhole does not exists foreign matter. During the rolling process, the maximum equivalent stress exists in the bottom of the oil pit. Due to the two-sided rolling tension, the weakest area of aluminum foil exists in the connected parts between the oil pit site and the matte side pit, thus these connected parts are likely being ripped apart, and the aluminum foil structure continuity is destroyed with the advent of the isolated aluminum foil pinhole. As the number of rolling pass increases, the area ratio of the pinhole decreases. However, the area ratio of the pinhole increases with the rolling speed rising. With the foil matte side roughness reducing appropriately, and controlling the oil pit ratio of the foil smooth surface, the pinhole ratio will be effectively controlled.