Keywords: heating, electric furnace, industrial furnace, automatic adjustment, vacuum, Carburization,

explain in detail the six major defects of improper heating of industrial electric furnaces

　　Industrial electric furnace equipment is a complete set, including electric furnace body, power equipment, switch, auxiliary electrical appliances, vacuum equipment, detection and control instruments, automatic adjustment system, and furnace mechanical equipment. One of the most important steps in the use of industrial electric furnaces is the heating of industrial electric furnaces. Once the industrial electric furnaces are improperly heated, there will be six major defects.

First: Overheating
　　Overheating refers to the phenomenon of coarse grains caused by the heating temperature of the metal blank being too high, or staying too long within the specified forging and heat treatment temperature ranges, or the temperature rising too high due to thermal effect.

Second: Decarburization
　　Decarburization refers to the phenomenon that the carbon on the surface layer of metal is oxidized at high temperature, making the carbon content on the surface layer significantly lower than that inside. The depth of the decarburized layer is related to the composition of the steel, the composition of the furnace gas, the temperature and the holding time at this temperature. Heating in an oxidizing atmosphere is prone to decarburization, high carbon steel is prone to decarburization, and steel with a large amount of silicon is also prone to decarburization. Decarburization reduces the strength and fatigue properties of the parts and weakens the wear resistance.

Third: Carburization
　　Carburization occurs on the surface or part of the surface of the forging heated by the electric furnace. Sometimes the thickness of the carburizing layer is 1.5~1.6mm, the carbon content of the carburizing layer is about 1%, and the carbon content of local points even exceeds 2%, resulting in ledeburite tissue. This is mainly in the case of heating of the oil furnace, when the billet is located close to the nozzle of the oil furnace or just in the area where the two nozzles cross spray fuel, because the oil and air are not mixed well, the combustion is incomplete, and as a result, a reducing carburizing atmosphere is formed on the surface of the billet, thereby producing the effect of surface carburization. Carburization makes the machining performance of forgings worse, and it is easy to cut when cutting.

Fourth: Heating Cracks
　　When heating large steel ingots with large cross-sectional dimensions and high-temperature alloy steel blanks with poor thermal conductivity, if the heating speed in the low temperature stage is too fast, the billet will have a large thermal stress due to the large temperature difference between the inside and the outside. In addition, at this time, the blank has poor plasticity due to low temperature. If the value of thermal stress exceeds the strength limit of the blank, a radial heating crack from the center to the periphery will be generated, causing the entire section to crack.

Fifth: Copper brittleness
　　Copper brittleness is cracked on the surface of the forging. When observed at high magnification, there is a light yellow copper distribution along the grain boundary. When the billet is heated, such as the remaining oxidized copper chips in the furnace, the oxidized steel is reduced to free copper at high temperature, and the molten steel atoms extend along the austenite grain boundary, weakening the relationship between grains. In addition, when the copper content in the steel is high, if heated in an oxidizing atmosphere, a copper-rich layer is formed under the scale, which also causes the steel to be brittle.

Sixth: Overburning
　　Overburning means that the heating temperature of the metal blank is too high or the residence time in the high temperature heating zone is too long, and oxygen and other oxidizing gases in the furnace penetrate into the gaps between the metal grains, and with iron, sulfur, carbon and other oxidation, the formation of eutectic eutectic oxide, destroy the contact between the grains, so that the plasticity of the material decreased sharply. If the metal is severely burned, it will crack with a light blow when it is removed, and transverse cracks will appear at the burned place when it is pulled long.

　　The above six major defects are caused by improper heating of industrial electric furnaces. Therefore, the influence of traditional Chinese medicine on the heating process of industrial electric furnace equipment should be paid attention to, the abnormal changes in internal structure and the temperature should be uniform.

More Explain in detail the six major defects of improper heating of industrial electric furnaces.: www.quenchtank.com/view-90.html