Semisolid Casting of Automotive Component: Water Pump Lid

Water pump lid is selected as the automotive component to be cast using semisolid casting technology. Semisolid feedstock of alloy A357 was produced by a vertical continuous DC casting with electromagnetic stirring. Non-dendritic structure was obtained in the feedstock billets. A 6-station induction heating system was developed for feedstock billet reheating. Multi-stage reheating and well controlled reheating process resulted in a uniform temperature profile in the billet. Semisolid casting was carried out in a conventional high pressure die casting machine. Die design and casting parameters were adjusted to be suitable for semisolid casting. Compared with the conventional liquid melt casting, semisolid casting resulted in a much higher microstructural integrity with reduced shrinkage porosity.