Abstract: A moulding device having a moulding block with a moulding cavity formed therein. A chamber is connected to the cavity and has a mouth where the chamber is connected to the moulding cavity. A closing member is provided between the chamber and the cavity which is moveable from a first position in which the mouth of the chamber is sealed to allow the chamber to be charged with a molten substance while the piston is retracted to a second position which forms a narrow orifice such that a fine spray or jet or film of molten substance is forced at a high velocity through the narrow orifice to form a fine grain coating on the inner surface of the moulding cavity. The closing member can then be further retracted to provide for a second phase of molten substance injection which is carried out until the moulding cavity is full.

Abstract: The invention relates to a magnesium alloy particularly useful for squeeze casting containing 10 to 25% zinc, 0.5 to 5% copper and 0.25 to 4% silicon, the balance being magnesium and aluminum being substantially absent from the alloy. Additions may include up to 1% calcium with a preferred 0.3% calcium, and 0.002 to 0.005% beryllium. The preferred composition is 12% zinc, 1% copper, 1% silicon, balance magnesium, although 0.3% calcium is a preferred addition to this alloy.The alloy is particularly useful for squeeze casting of automotive and aerospace components.