Patent ID: 6450241
Filing Date: 2002-09-17
Classification: B22D

Abstract:
A method for continuous or semi-continuous casting of metal, comprising the steps of:supplying hot melt to a cooled continuous casting mold, cooling and forming the melt to an at least partly solidified strand, by passing the partly solidified melt through the mold, and applying a high frequency magnetic field having a base frequency of from 50 Hz or more to act on the melt at the top end of the mold using an inductive coil for developing heat and compressive forces in the melt acting to separate the melt from the mold wall, supplying a current from a power supply to the coil for generating the magnetic high frequency field, controlling the supplied current in a pulsed, amplitude modulated manner with an amplitude modulated modulation frequency of about 10 Hz or less, thereby achieving substantially full amplitude of the amplitude modulated current within a rise time corresponding to about 1 cycle of the base frequency or less at the start of a pulse.