Utilizing a combination of MF-Power and HF-Power at the same time on one common inductor, Eldec Induction developed generators capable of creating a real dual-frequency, true-contour hardening process called "simultaneous dual frequency" hardening or SDF^®. These generators can also perform normally, using either HF or MF power supplies in separate operations for surface hardening.The SDF® output powers of MF : HF are infinitely variable in the ratio 1 : 99 until 99 : 1.

The effect of the possibilities with Simultaneous Dual Frequency can be seen in the three photos to the left, from top to bottom showing heating of a gear.

The photos show the following SDF^® Ratios:

Top (Root effective)
MF : HF=90 :10
Middle (Tooth effective)
MF : HF=10 : 90
Bottom (True-Contour effective)
MF : HF= 70 :30
Internal Gear Simultaneous Dual Frequency Hardened
Heat Time 0.6 seconds, 300 kW MF Power, 150 kW HF Power

Eldec Induction is the pioneer and sole provider of the revolutionary Simultaneous Dual Frequency induction power supplies and heat treating systems. We provide a complete line of standard CNC controlled, induction heat treating systems and solutions. Eldec Induction specializes in custom engineered systems for all induction heating applications.

You can read more about the SDF^® process and possible applications in the following articles:

Surface hardening using the simultaneous dual frequency method
(Metallurgia, March/April 2003)


SDF induction heating provides accurate contour hardening of PM parts
(Induction Heating)

The simultaneous dual frequency method of inductive gear hardening
(Gear Solutions, May 2003)

Simultaneous dual frequency induction hardening
(Heat Treating Progress, April/May 2003)