Influence of Homogenizing on the Properties of Cast Aluminium Products

Annealing treatments are of the same importance in aluminium processing as casting, extruding or rolling. Numerous properties are influenced and optimized by annealing processes. The first annealing treatment given to aluminium, is the so-called “homogenizing” in most cases. It must be made quite clear from the beginning that the designation “homogenizing” is not absolutely correct, since in many cases not the homogeneous, but the heterogeneous structure obtained by annealing with segregations has the better properties. For the sake of simplicity, however, the term “homogenizing” will be maintained. Furthermore, in the modern way of looking at things, no longer annealing to a predetermined temperature level is to be assessed on its own but the full annealing cycle consisting of heating — annealing — cooling and reheating to the temperature by hot forming of the primary metal. That this is necessary has been proved in recent examinations of the influence of small additions of manganese in AlMgSi alloys on the heat formability (1).