W. Schwenk, Eldec Induction U.S.A., Inc., Auburn Hills, MI

Summary: Inductive hardening of parts with complex surfaces such as gears, with only HF results in a hardening bias of the tips and sides of gear teeth. Conversely, with the use of MF, the emphasis is in the root areas of the gear teeth. The uniform surface hardening with a pattern corresponding to the contours of a gear has not yet been obtained with either HF or MF. However, it is now possible to utilize the inherent properties of both these frequencies simultaneously to produce a uniformly surfaced hardened gear inductively. The Simultaneous Dual Frequency method of induction hardening uses both HF and MF simultaneously through a common inductor to exactly follow the contours of the gear and its teeth. Through variations of the HF and MF formula mix, different size gears can be optimally hardened. The presentation that follows will outline the basics of simultaneous dual frequency, its benefits and examples of some of the new projects that now can be taken on.