Vacuum Furnace Temperature Control
Vacuum furnace temperature control system is mainly composed of thyristor trigger excitation device, single-chip computer fuzzy controller, thermocouple sensor, magnetic voltage regulator and recorder, which together with the controlled object (molybdenum wire heater in vacuum heating chamber) constitute a direct digital control (DDC) system, and the whole control constitutes a closed-loop fine-tuning system.
Temperature control, heating and atmosphere structure of vacuum furnace will directly affect product quality and production of vacuum furnace. In forging furnace, the melting resistance can be reduced by increasing temperature, but too high temperature will lead to oxidation or burning of grain, which seriously affects the quality of vacuum furnace. During the heat treatment process, if the steel is heated to a higher critical temperature and then cooled suddenly, if the steel with higher hardness and strength is heated to a lower temperature and then cooled slowly, the steel will be more elastic.
After calculating the deviation between the set process curve and the test signal, the vacuum furnace single chip computer uses the fuzzy control algorithm to make the fuzzy inference, then sends out the control signal, controls the conduction angle of the thyristor through the thyristor trigger device, so as to control its output voltage. This AC adjustable voltage is then converted into DC voltage by the diode rectifier to excite the magnetic regulator to control the magnetization. The output power of the voltage regulator can be continuously adjusted and heated by resistance to achieve the purpose of temperature control.
Many kinds of small non-oxidizing heating furnaces can be adopted for the purpose of surface finish and dimensional accuracy, or to reduce metal oxidation, thereby protecting dies and reducing processing allowances. The open flame less non-oxidation heating furnace can reduce the fuel produced by incomplete combustion of gas, and the oxidation burning loss of heating workpiece can be reduced by 0.6%.