SUTE1025 Low Voltage Electric Heater Welding Preheating Site
A heating furnace is equipment used to heat materials or workpieces. According to the heat source, there are fuel heating furnaces, resistance heating furnaces, induction heating furnaces, microwave heating furnaces, etc. Their applications span many industries such as petroleum, chemical, metallurgy, machinery, heat treatment, surface treatment, building materials, electronics, materials, light industry, daily chemicals, pharmaceuticals, and more.
According to the furnace temperature distribution, the furnace chamber is divided into a preheating zone, a heating zone, and a soaking zone along the length direction; the temperature at the feed end is lower, which is the preheating zone, and its function is to utilize the heat of the furnace gas to improve the thermal efficiency of the furnace. The heating zone is the main heat supply zone, with higher furnace gas temperature to facilitate rapid heating. The soaking zone is located at the discharge end, where the temperature difference between the furnace gas and the metal material is very small, ensuring uniform temperature across the cross-section of the discharged billet. Furnaces used for heating small cross-section billets only have a preheating zone and a heating zone. Conventionally, the furnace sections are also divided according to the heating zones where burners are installed. Based on the number of heating zones, the furnace is called a single-zone, two-zone, up to five-zone, six-zone, etc. In the 1950s and 1960s, due to the increased capacity of rolling mills and the limitation of the length of pusher-type furnaces by the pushing length, heating zones began to be added at the feed end, eliminating the non-heating preheating zone to increase productivity per unit area of the furnace hearth. Using this type of furnace to heat slabs, the output per unit area of the hearth reached 900-1000 kg/(m²·h), and the heat consumption was about (0.5-0.65)×106 kcal/ton. Since the 1970s, due to the need for energy conservation and the emergence of new walking beam furnaces that allow for increased furnace length, non-heating preheating zones have been added again, with the output per unit area of the hearth at 600-650 kg/(m²·h) and heat consumption about (0.3-0.5)×106 kcal/ton.
Continuous heating furnace usually uses gaseous fuel, heavy oil, or pulverized coal, and some burn lump coal. To effectively utilize waste gas heat, heat exchangers for preheating air and gas, or waste heat boilers, are installed in the flue.
