Method for magnetic flux compensation in a directional solidification furnace utilizing a stationary secondary coil

An induction furnace assembly comprising:

• a chamber containing a mold;
• a primary inductive coil coupled to said chamber;
• a susceptor surrounding said chamber between said primary inductive coil and said mold;
• at least one secondary compensation coil fixed to said chamber between said susceptor and said mold;
• said at least one secondary compensation coil configured to generate a control field configured to control a magnetic flux leakage past said susceptor from said primary induction coil;
• and
• a controller coupled to at least one flux sensor located within said chamber, wherein said controller is configured to generate a control signal responsive to an input from at least one of a flux sensor and a flux set point;
• wherein said magnetic flux leakage is detectable by said at least one flux sensor at a predetermined location within said chamber.

A process for directional solidification of a cast part comprising:

• generating an electromagnetic field from a primary inductive coil coupled to a chamber of an induction furnace, wherein said electromagnetic field includes a magnetic field leakage that passes a susceptor coupled to said chamber between said primary inductive coil and a mold;
• controlling said magnetic field leakage entering said mold inside said chamber by use of an applied magnetic control field generated by at least one secondary compensation coil fixed between said susceptor and said mold in said chamber by employing a controller coupled to at least one flux sensor located within said chamber, wherein said controller is configured to generate a control signal responsive to an input from at least one of a flux sensor and a flux set point;
• wherein said magnetic field leakage is detectable by said at least one flux sensor at a predetermined location within said chamber;
• sensing said magnetic field leakage past the susceptor within the chamber with said at least one flux sensor;
• and
• casting a part within said mold from a molten material.