Most aluminum foil rolls are made from 99.0%-99.5% industrial pure aluminum. Generally speaking, the higher the purity, the lower the tensile strength and the higher the elongation. Increasing the impurity content can increase the tensile strength and reduce the elongation. However, when the purity of aluminum is too low, the brittleness of the material increases, the rolling performance becomes poor, and pinholes are prone to occur. Therefore, low-purity aluminum is not suitable for rolling into aluminum foil rolls.
But too high a purity is not conducive to processing. Although the elongation of aluminum has increased, serious adhesion is prone to occur in the first pass of rolling, especially after intermediate annealing, resulting in whitening of the surface of the roll, poor lubrication, and a decrease in the friction coefficient between the rolls. increase. Rolling parts and causing pinholes. Therefore, when rolling high-purity aluminum foil, there is no need to perform intermediate annealing on the aluminum foil blank and directly process it to the finished thickness (0.05 mm).
Impurities can also affect the purity of aluminum foil rolls. Industrial pure aluminum usually contains impurities such as Fe, Si, Cu, Mn, Ti, B, and C. Some impurities are inherently present, and some are intentionally added as grain refiners, such as Ti and B. Although the content of these impurities is relatively small, they have a very important impact on the mechanical properties and processing properties of aluminum foil rolls.
