Induction Heating Valve Head Forย Stress Testing With Induction Heating Equipment
Objective To heat the face of an engine valve head to 900ยฐF andย maintain the temperature for an extended time, highย temperature stress test.
Material Engine valve head (two sizes), temperature sensing paint
Temperature 900 ยฐF
Frequency200ย kHz for large part; 271 kHz for smaller part
Equipment DW-UHF-10KW Induction Heatingย power supply, remote heatย station with one 0.66 mF capacitor, a specially designed, multiturnย induction coil and an optical pyrometer.
Process A specially designed multi-turn pancake coil was used toย provide uniform heat to the part. To provide optimum coupling,ย the face of the valve head was placed approximately 3/8โ awayย from the coil. RF induction power was applied for 4 minutes to heat theย larger valve to 900ยฐF; the smaller valve head required 2ย minutes to reach the same temperature. For closed-loopย temperature control, the optical pyrometer was then used toย maintain the temperature at 900ยฐF.
Results Uniform and repeatable results were obtained with the
DAWEIย power supply and induction coil at 900ยฐF.ย Depending on the part size, the correct temperature wasย reached in 2 to 4 minutes.