An apparatus for magnetic induction hardening of a workpiece includes a magnetic tool having a body portion formed of a generally non-magnetic material. The body portion has a surface configured to be positioned in close proximity to the workpiece being hardened. The apparatus further includes a magnetic arrangement coupled to the body portion at or adjacent the surface of the body portion and configured to provide regions of alternating polarity. A workpiece holder is configured to support the workpiece in close proximity to the surface of the magnetic tool. A drive arrangement for rotating the magnetic tool relative to the workpiece holder about an axis of rotation is provided to induce heating of the workpiece to achieve a temperature in the austenitic range of the workpiece resulting in hardening of the workpiece through a microstructural transformation.

A system and method of induction heat treating a gear includes a workstation. The workstation has a power source, an inductor coil, and a rotational mechanism. The gear is induction heat treated at a first portion of the gear and a second portion of the gear remains untreated by induction hardening. The gear has an inner surface. The inner surface includes the first portion and the second portion. The first portion has a first width. The second portion has a second width. The inductor coil includes at least one heating loop and at least one non-heating loop. The inductor coil is energized to a predetermined frequency to create an alternating magnetic field, where the alternating magnetic field developed in the heating loop induces an eddy current in the first portion of the gear.