eldec has many years of experience in inductive hardening and tempering of diverse workpieces. In addition to single-frequency solutions, our focus in the area of hardening applications lies on accurate contour hardening and thus on the use of our SDF^® two-frequency technology.

In this process, an inductor is supplied simultaneously with MF (medium frequency 10-25 kHz) and HF (high frequency 150-350 kHz) energy. Depending on the workpiece geometry, the MF and HF power components are adjusted to produce accurate contour heating and, due to the very rapid quenching, accurate contour hardening. The HF energy mainly heats the tips of the teeth and the MF energy heats the tooth root.
It is critical here that high power components are able to act on the surface to be hardened in a very short time without significant heat dissipation being able to take place. Hardness is produced where it belongs: in the surface layer. This saves energy and considerably reduces distortions and thus rework like grinding, lapping or hard turning.

Our SDF^® generators range from power values of 15 kW to 3000 kW. The SDF^® generators are equipped with two frequency converters in IGBT transistor technology. With automatic adaptation over the entire frequency range, the IGBT transistor technology with pulse width modulation (PWM) or pulse pack control (PPC) ensures high efficiency. The MF and HF power components are continuously adjustable in the range from 2% to 100%, with the high-frequency oscillation being superimposed on the medium-frequency basic oscillation. The amplitudes of both oscillations can be controlled separately so that the power component of both frequencies, and thus also the case-hardening depth, can be adjusted separately as needed for the component.

Some videos of various sample applications are adjacent.