Influence of Different Roll Casting Conditions on Casting Microstructure

Abstract

The changes of roll casting microstructure under different casting conditions on experimental casting machine was studied, which showed that solidification microstructure is different with different casting speed and thickness. When the casting speed is 1.3m/min,the thickness of strip is 6mm, coarse columnar grain dominates the solidification structure; when it continuously increases to 4m/min, the thickness of strip is 3mm, aluminum strip shows as hybrid organization with columnar grains in two sides and small equiaxed grains in the center; when the casting speed is over 12m/min,the thickness of strip is 1.75mm, columnar grains all convert into equiaxed grains in solidification structure. The deformation microstructures are different with the different casting speed and thickness of strip. When the casting speed is 0.9m/min, the thickness of strip is 6mm, typical processing flow lines come into being along longitudinal direction and transverse direction shows as squashed grains without re-crystallization. When the casting speed is 5.4m/min, the thickness of strip is 2.5mm, microstructure of aluminum strip becomes chevron organization from columnar crystal, there is a condensate in the center of aluminum strip, and the deformation of outer metal is more serious than inner, incomplete dynamic recrystallized grains come into being in the outer metal of the aluminum strip.