By heating method and indirect resistance furnace into direct heating heating two.
Direct resistance heating furnace, direct current through the material, electric power is concentrated in the material itself, so the material heated quickly, designed for rapid heating process, such as forging heating. The resistance-furnace materials can be heated to very high temperatures, for example carbon graphite furnace can heat the material to more than 2,500 degrees. Heat resistance furnace can be made directly into the vacuum resistance furnace or pass gas resistance furnace, powder metallurgy, often used for sintered tungsten, tantalum, niobium and other products. This stove heating should be used note:
① in order for the material to be heated evenly, requires every part of the materials conductivity and conductive cross-section;
II due to the resistor material is quite small, to achieve the required heating power, current, so transmission contact electrodes and the material is better to avoid arc burning material, and less resistance to electricity transmission bus, to reducing circuit losses;
Most of the resistance furnace is heated by electric resistance furnace, which is designed to achieve transformation of electro-thermal resistance, known as the electric heating element, made of it in the furnace to heat materials
The electric furnace shell made from steel plate, lining of the furnace refractory ceramic fibers inside material.
Most common electric heating element is Fe-CR-Al electrothermal electric heating element, silicon carbide rods, Nickel chromium and molybdenum disilicide, silicon carbide, zirconium diboride ceramic heating element.
As needed, the furnace atmosphere atmosphere can be ordinary, protective atmosphere or in a vacuum. General supply voltage 220 v or 380 v, adjustable voltage transformer, if necessary. Small oven (< 10-kilowatt) single phase power supply, large three-phase power supply. For single variety and large batch of materials, suitable for continuous furnace heating. Temperature of less than 700-resistance furnace, most equipment blowers to enhance heat transfer in the furnace to ensure even heating. Used to melt the fusible metal (lead, lead-bismuth alloy, aluminum and magnesium alloy) resistance furnace, Crucible Furnace reverberatory furnace or melt pools, installation of electric heating element on top of the stove. ESR is a change from the dross of electrical resistance furnace (see ESR).