The nature and application of resistance furnace

The use of current so that the furnace heating element or heating medium heat, thereby heating the workpiece or material for industrial furnaces. Resistance furnace in the machinery industry for metal heating before forging, metal heat treatment heating, brazing, sintering powder metallurgy, glass, ceramic firing and annealing, low melting point metal melting, sand and paint film layer drying.
Since the discovery of heating effect of current (ie Lenz Heights - Joule's law) after heating method first used in household appliances, small electric stove and later used in the laboratory. With the invention of nickel-chromium alloy, into the 1920s, resistance furnace has been widely used in industry. Industrial use of resistance furnace generally consists of heating elements, masonry, metal casing, door, furnace mechanical and electrical control systems and other components. Heating power from less than one kilowatt to thousands of kilowatts. Working temperature below 650 ℃ low temperature furnace; 650 ~ 1000 ℃ in temperature for the oven; 1000 ℃ above furnace. At high temperature and medium temperature furnace heating mainly by radiation. In the low-temperature furnace convection heating methods places, electric components are mounted on the duct, through the fan forced air circulation furnace in order to enhance the convective heat transfer. There chamber resistance furnace, pit, car type, pusher, stepping, muffle type and tunnel type and other types. Controlled atmosphere furnace, vacuum furnace, furnace, etc. are also flowing particle resistance furnace.
Heating element has high heat resistance and high temperature strength, low temperature coefficient of resistance and good chemical stability. Materials commonly used in metal and nonmetal two categories. Metal heating element materials are nickel-chromium alloy, chromium-aluminum alloy, tungsten, molybdenum, tantalum, are generally made of spiral, wavy line, and a wave plate with a waveform. Non-metallic materials are silicon carbide heating elements, molybdenum disilicide, graphite and carbon, are generally made of rods, tubes, plates, with other shapes. The distribution of the heating element and the line connection, according to the size of the furnace and the furnace power requirements.
Resistance furnace and flame furnace, has a simple structure, temperature uniformity, easy to control, heating, good quality, no dust, no noise, etc., but the use of the higher fees.