Influence of 3104 Alloy Microstructure on Sheet Performance in Ironing Aluminum Beverage Cans

This paper studied sizes and distribution of Fe-containing constituents in 3104 ingots, their breakage during subsequent rolling and the resultant influence on the final gauge sheet performance in ironing beverage cans. It was observed that coarse Fe-containing constituents had retained on the sheet surface from the ingot scalped by 7 mm per rolling face. They broke up during rolling by 7.5 times and mostly in reversing mill, but they still were coarse on the final gauge sheet that caused pitting formation on can side walls during ironing at body makers. The microstructure of the sheet rolled from 20 mm scalped ingot was fine and did not contain constituents over 20 μm in size that resulted in its robust performance at body makers. It was shown that Fe-containing constituents were extremely critical for the sheet microstructure and its subsequent ironing performance at body makers. The ingot scalping depth should be determined based on their sizes and distribution below the rolling faces to avoid coarse constituent remains on the sheet surface.