Patent ID: 6634412
Filing Date: 2003-10-21
Classification: B22D,Y10S

Abstract:
A process for producing a casting of a magnesium alloy, using a pressure casting machine having a mould or die which defines a die cavity, wherein the process includes the steps of supplying molten metal to a metal flow system which includes a die or mould tool means which defines at least one runner of the system into which molten magnesium allow is received and from which alloy is injected into the die cavity, and controlling metal flow velocities in the system whereby substantially all of the metal flowing throughout the die cavity is in a semi-solid state, and wherein said controlling includes causing the alloy from the runner to flow through a controlled expansion region whereby metal flow spreads laterally in said region, with respect to its direction of injection, with a resultant reduction in its flow velocity relative to its velocity in the runner; andwherein the system is operable to achieve a velocity of molten metal through the runner with the range of about 140 m/s to 165 m/s.