In order to make up wrought Al-1.63mass%Si-0.54mass%Mg alloy billets for thixoforming and thxiocasting, semisolid continuous casting was carried out. An inclined cooling plate was used to make numerous a aluminium crystal seeds which dispersed in the molten alloy before casting. Seeds of primary alpha aluminium crystals in the molten alloy grew in the tundish prior to entering the mould of the casting machine.