A brief introduction about resistance furnace:
In current through a conductor joule heat generated by the electric furnace for the heat source. According to the electric heating way, resistance furnace is divided into two directly heating and indirectly heating. In direct heating resistance furnace, current directly through the material, because of electric power concentrated in the material itself, so the material heat quickly, is suitable for the requirements of rapid heating process, such as forging billet heating.
The resistance furnace can be heated to very high temperatures, the supplies graphitizing furnace carbon materials, for example, can put the material to the heated above 2500 ℃. Directly is made vacuum resistance furnace heat resistance or protective gas resistance furnace, heating furnace in powder metallurgy, commonly used in sintering tungsten, tantalum, niobium and other products. Using this stove heating should be paid attention to:
(1) to make the material is heated evenly to each part of the material of conductive section and conductivity is consistent;
(2) due to the resistance material itself is fairly small, to achieve the required heating power, working current is quite big, therefore power electrode and material contact is better, so as to avoid the arc burning material, and the resistance of the power bus, to reduce the circuit loss;
Most of the resistance furnace is indirect heating resistance furnace, which is equipped with dedicated to the realization of electrical and thermal transition resistance, called the electric heating body, by its pass in the furnace the heat materials.
This kind of electric furnace shell made of steel plate, build by laying bricks or stones of the chamber of a stove or furnace lining refractory materials such as ceramic fiber, put inside the material.
The most commonly used electric heating body is iron chromium aluminum electric heating body, nickel chromium, silicon carbide rods and molybdenum disi1icide electric heating body, silicon carbide, zirconium boride ceramic composite heating element. According to need, furnace atmosphere, protective atmosphere or vacuum can be a normal atmosphere.
The general power supply voltage 220 v or 380 v, the middle of the configuration of adjustable voltage transformer when necessary. Small furnace (< 10 kw) single-phase power supply, three-phase power supply large furnace. For varieties of a single, large batch of shoes materials, appropriate USES continuous heating furnace.
Temperature is below 700 - resistance furnace, most device blower, with enhancing heat transfer in furnace, ensure uniform heating.
Used to melt fusible metal (lead, lead, bismuth alloys, aluminum and magnesium and its alloys, etc.) of the resistance furnace, can make a crucible furnace; Or make it have a reverberatory furnace of molten pool, installing electric heating body on top. Electroslag furnace is made of slag change electric resistance furnace (esr).