AGMA 11FTM24 PDF

Induction hardening of gear teeth is well known for its challenges, but also for its potential for improved quality and process control. For complex geometric parts like gears, the power density and induction frequency need to be adjusted very precisely to achieve the required hardening pattern. Since 1940s it is known that working with two simultaneous frequencies (1-15 kHz and 200-20000 kHz) is the optimal way to heat a geared part to hardening temperature. The key point in this process is that the medium frequency (about 10 kHz) affects primarily the tooth root and the high frequency affects first of all the tip of the tooth and the flanks. The right combination of the power densities of medium- and high frequency energy values and the heating time are the crucial factors to reach a contour true heating pattern and, thereby, a contour true hardening pattern. The authors will describe the state of the art of induction hardening of gears with simultaneous dual frequency using some examples of use and present the possibilities to manipulate the hardening pattern in a positive way for different gear geometries.