Induction Tempering Spring

Objective Temper a spring by heating it to 300°C (570°F) in 2 – 4 seconds
Material Stainless steel AISI 302 springs- different length from 60 to
110 mm – outer diameters 8 mm.- wire diameter from 0.3 to 0.6 mm
Temperature 300°C (570°F)
Frequency 326 kHz
Equipment • Power of 6kW induction heating system
• remote workhead, two 0.33μF capacitors (total 0.66μF)
• multi-turn C-channel coil developed for this application
Process Springs are mounted on non-metallic mandrels to facilitate loading and unloading and are placed inside the coil (picture). Power is applied for 2 – 4 seconds, completing the tempering process. The C-channel distributes the heating evenly and enables the convenient staging and removal of the springs.
Results/Benefits Efficiency: Energy is applied directly to the springs only; surrounding air and fixturing are not heated.
Precision: temperature and duration of process are controlled Convenience: method integrates into a continuous process

Tempering Spring