EXPERIMENTAL INVESTIGATION OF THERMOMECHANICAL EFFECTS DURING DIRECT CHILL AND ELECTROMAGNETIC CASTING OF ALUMINUM-ALLOYS

The deformation and the temperature field within direct chill (DC) and electromagnetic (EM) cast aluminum ingots have been measured in situ using a simple experimental setup. The deformation of the cross sectio n of the cold ingots has also been characterized as a function of the casting speed, alloy composition, and inoculation condition. The pull- in of the lateral rolling faces has been found to occur in two sequenc es for DC cast ingots, whereas that associated with electromagnetic ca sting (EMC) was continuous. The pull-in was maximum at the center of t hese faces (about 7 to 9 pet) and strongly depended upon the casting s peed. Near the short sides of the ingots, the deformation was only abo ut 2 pct and was nearly independent of the casting parameters and allo y composition. Based upon these measurements, it was concluded that th e pull-in of the rolling faces was mainly due to the bending of the in gots induced by the thermal stresses. This conclusion was further supp orted by a simple two-dimensional thermoelastic model.