Aluminum alloy 3004 (Al-1.0 Mn-1.0 Mg) is the predominant material of choice for use in rigid beverage containers. The mechanical property requirements of the draw and iron forming operation dictate careful control of the aluminum sheet production parameters. The demand for ever lighter weight beverage containers has also continued to place increased demands on the strength requirements of the aluminum can stock. To achieve the strength requirements, the sheet must be produced in a highly cold-worked state. A practical consequence of this required level of cold work is pronounced mechanical and crystallographic anisotropy. Without careful control of can stock production parameters, pronounced rolling textures can lead to an undesirable directionality of properties that produce ears, formed during the deep drawing operation of can making, located 45° to the rolling direction. Figure 1 shows the rolling texture ears in a drawn and ironed beverage can.

This article illustrates the minimization and control of rolling texture earing in cold rolled 3004 alloy beverage can stock through modification of the fabricating process, application of metallurgical theory, optimization of hot rolling practice through empirical experimentation, and process control practices.