Experimental investigation of factors affecting surface quality of Al–Cu alloys ingots

For rapid chilling, the cast surface will often exhibit a particular group of defects characterized by ripples and laps. This work was carried out to experimentally investigate the influences of alloy solute content, melt superheat, transient metal/mold heat transfer coefficient and teeming speed on the surface quality of Al–Cu alloys ingots in the range of pure Al and the eutectic composition. The surface quality was shown to be enhanced by the increase of melt superheat and of teeming speed and the decrease of the metal/mold heat transfer efficiency. It was shown that the best surface quality is associated with a Cu content close to the maximum solidification range at about 5 wt.% Cu.