Patent ID: 7225858

Claim:
A method of producing a semi-solid metal alloy for use in forming a final product, which method includes providing a treatment zone which is defined by an AC induction coil and charge cooling means; introducing a charge of molten metal contained within a container into the treatment zone by displacing said container along a linear path from a starting position which is aligned with the treatment zone; simultaneously subjecting the charge to an electromagnetically induced force field and controlled cooling in said treatment zone, said force field being induced by supplying said induction coil with current in the range of 100 to 12000 amps and at a frequency of between 60 to 30000 Hz thereby to provide a force field intensity which is sufficient to induce turbulence and vibratory motion in the charge during cooling to promote primary globular crystal formation instead of dendritic crystal formation; and displacing said container from the treatment zone by urging a subsequent container charged with molten metal into the treatment zone along said linear path.