Study on Cracks of Last Freeze in Al-Mg Alloy Flat Ingots

Abstract

In casting of Al-Mg alloy, especially in the aluminum alloy with high Mg content of more than 4 wt.% Mg, some cold cracks were found in last freeze of the flat ingots. The depth of cracks was bigger than 200 mm. The size of scrap removal of ingot was thus increased by 70 mm or more, and the yield of the flat ingots was greatly affected. Air cooling time of more than 20 min after casting was a better to reduce cracks in last freeze of Al-Mg alloy flat ingots.