The fuel of industrial furnaces is also following the development of fuel capital and the advancement of fuel conversion skills, and the selection of solid fuels such as lump coal, coke, and pulverized coal is gradually changing to gas and liquids such as producer gas, city gas, natural gas, diesel, and fuel oil. Fuel, and developed various incineration equipment compatible with the fuel used.
The structure, heating process, temperature control and atmosphere of the industrial furnace will directly affect the quality of processed products. In the casting heating furnace, increasing the heating temperature of the metal can reduce the deformation resistance, but if the temperature is too high, it will cause grain growth, oxidation or over-burning, which will seriously affect the quality of the workpiece. In the heat treatment process, if the steel is heated to a certain point above the critical temperature and then cooled suddenly, the hardness and strength of the steel can be improved; if the steel is slowly cooled after heating to a certain point below the critical temperature, the hardness of the steel can be increased Decline and improve patience.
In order to obtain workpieces with accurate dimensions and smooth appearance, or to reduce metal oxidation to achieve the purpose of maintaining molds and reducing machining allowances, various oxidation-less heating furnaces can be selected. In an open-flame heating furnace with less and no oxidation, incomplete incineration of fuel is used to generate recoverable gas. Heating the workpiece in it can reduce the oxidation burn loss rate to less than 0.3%.
The controllable atmosphere furnace is the use of artificially prepared atmosphere, which can be passed into the furnace for gas carburizing, carbonitriding, bright quenching, normalizing, annealing and other heat treatments: to achieve the intention of changing the metallographic arrangement and improving the mechanical properties of the workpiece. In the movable particle furnace, the incineration gas of fuel or other fluidizing agent applied from the outside is used to force the graphite particles or other lazy particle layers on the furnace bed. The workpiece can be buried in the particle layer to complete the intensified heating. Various non-oxidizing heating such as carburizing and nitriding. In the salt bath furnace, the molten salt is used as the heating medium to prevent oxidation and decarburization of the workpiece. The smelting of cast iron in the cupola is often affected by the quality of coke, the air supply method, the condition of the charge and the air temperature, which makes the smelting process difficult to stabilize and difficult to obtain high-quality molten iron. The hot-blast cupola can effectively increase the temperature of molten iron, reduce alloy burning loss, reduce the oxidation rate of molten iron, and then produce high-grade cast iron.
Following the emergence of coreless induction furnaces, cupolas have a tendency to be gradually replaced. The smelting operation of this kind of induction furnace is not restricted by any cast iron grade. It can quickly change from smelting one grade of cast iron to smelting another grade of cast iron, which is conducive to improving the quality of molten iron. Some special alloy steels, such as ultra-low-carbon stainless steel and steel used for rolls and steam turbine rotors, require the molten steel smelted in an open hearth or electric arc furnace to be vacuum degassed and argon agitated to remove impurities in the refining furnace. High-quality molten steel with high purity and large capacity.