60Hz Line Frequency for Deep Heating With Induction

As an industry process, induction heating was originally only a 60Hz line frequency technology (early 1900’s). A century later, induction heating can be performed across a very wide range of frequencies. Even with all these available frequency choices, there are applications that still benefit from 60Hz line frequency equipment. It is important to consider this when deep heating into a metallic workpiece is needed. Induction heating is a surface / sub-surface heating process using AC current applied to an induction coil. When energized, the induction coil produces an alternating magnetic field. With the metallic workpiece placed inside this magnetic field, a current is induced to flow on the surface of the workpiece. This results in surface heating of the workpiece. The depth of this surface heating is dependent upon the frequency of the applied coil current. Use of 60Hz provides maximum depth of heating at and below the surface. Early adoption of line frequency heating was for melting various metals held in a crucible. While this is still done today, there are many other practical applications. These include heating for shrink fit, curing, annealing, tempering, bonding, and more. This presentation will provide details on this technology along with case studies.