Numerical Simulation of Air Gap Formation in Water-Cooled Mold Casting
While using water cooled mold to produce steel ingot, an air gap is generated between the ingot and the mold, which has an important influence on the ingot quality. The air gap formation law and its influence on the solidification process were calculated by used FE software Procast. It is shown that, air gap occurs in a few minutes after the solidification begins. In 75-100s later the gap reaches 0.2-0.5 mm and starts to influent the heat transport significantly, the rate of the temperature decrease becomes slower. When the solidification is finished, there is a lager gap on the two narrow surfaces than it on the other wide surfaces; and the gap on the two narrow surfaces is different. The air gap on the narrow surface close to the sprue has a width of 12-20 mm; on the other narrow surface away from the sprue has a width of 4-13 mm. The biggest gap on the two wide surfaces has a size about 6.5mm. For the air gap is formatted between the ingot shell and the ingot mold, the solidification time is 50% longer than that of without air gap.