Induction Heating Engine Valve

Objective To heat the face of an engine valve head to 900°F and maintain the temperature for an extended time, high
temperature stress test.
Material Engine valve head (two sizes), temperature sensing paint
Temperature 900 °F
Frequency 223 kHz for large part; 271 kHz for smaller part
Equipment Power of 10kW power supply, remote heat station with one 0.66 mF capacitor, a specially designed, multiturn induction coil and an optical pyrometer.
Process A specially designed multi-turn pancake coil was used to provide uniform heat to the part. To provide optimum coupling, the face of the valve head was placed approximately 3/8” away from the coil. RF power was applied for 4 minutes to heat the larger valve to 900°F; the smaller valve head required 2 minutes to reach the same temperature. For closed-loop temperature control, the optical pyrometer was then used to maintain the temperature at 900°F.
Results Uniform and repeatable results were obtained with the UIHM power supply and induction coil at 900°F.
Depending on the part size, the correct temperature was reached in 2 to 4 minutes.

Heating Engine Valve