Effect of casting conditions on aluminium metal quality

A study in a secondary alloy ingot producing plant was targeted to investigate the metal quality change in the holding furnace during secondary remelting of aluminum alloy LM24 (Al–8Si–3Cu–Fe). The investigation was an attempt to understand the effect of: (i) the use of diffusers (porous plugs integrated into the body of the furnace) and (ii) casting techniques involving different degrees of turbulence. Casting density and bifilm index were found to be useful parameters to assess metal quality. It was found that the metal quality was increased significantly, and was maintained high throughout the casting operation when: (i) diffusers were used and (ii) turbulence was reduced to a minimum.