Induction Heat Treating Oven
This is an induction heater I built capable of reaching temperatures up to 2000 degrees Fahrenheit. It is built using a induction heating circuit connected to a copper tube shaped into a coil. Within the coil is a graphite ingot mold which acts a heating element using electrical resistance to heat the mold and anything in it. Between the mold and the copper coil is high temperature insulation to keep the heat in and the copper coil from overheating. In addition a water pump is pushing water through the copper tube to keep it from getting too hot and burning. A PID temperature controller is used to control the temperature of the graphite mold and ensure a steady temperature is acheived.
How It's Built
I started with an induction heating module bought as unit. This produces the high frequency electricity that allows for the induction effect to take place. The heater is powered by a 36 volt 1000 watt power supply. A PID temperature controller is used to ensure the oven stays at a constant temperature. The PID controller sends signals to the main circuit through a solid state relay. Another 12 volt power supply is used to power fans and other electronics.
Heating Chamber
The small heating chamber uses a graphite ingot mold a heating element as well as a place to put the material being heat treated. The graphite is wrapped with high temperature insulation on all sides except for the top which is covered with with insulation fiberboard with a hole in the top for the thermocouple. This is all fitted into coil made with 1/4" copper piping. So the electricity running through the copper coil induces a high current electricity into the graphite mold heating with resistance heating.
Water Cooling
Water is pumped through the copper pipe In order to keep the copper from getting too hot. The water is held in a small reservoir with a small inside. Water is pumped through silicone tubing through the copper coil and back to the reservoir. This keeps the coil from overheating and the water stays cool for a few hours allowing me to heat treat many pieces of steel.