Induction furnaces can be divided into high frequency furnaces, intermediate frequency furnaces and industrial frequency furnaces according to the power frequency; according to the process purpose, they can be divided into melting furnaces, heating furnaces, heat treatment equipment and welding equipment; according to their structure, transmission mode, etc. sort. Commonly used induction furnaces are habitually grouped into hearted induction melting furnaces, induction melting furnaces, vacuum induction melting furnaces, induction hardening equipment and induction head thermal equipment, etc. The name of the smelting furnace is relative to the induction smelting furnace. The molten metal is contained in a crucible, so it is also called a crucible furnace. This type of furnace is mainly used for smelting and heat preservation of special steel, cast iron, non-ferrous metals and their alloys. The coreless furnace has many advantages such as high melting temperature, less impurity pollution, uniform alloy composition, and good working conditions. Compared with the cored furnace, the coreless furnace is easier to start and change the metal varieties, and it is more flexible to use, but its electric and thermal efficiency is far lower than that of the cored furnace. Due to the low surface temperature of the coreless furnace, it is not conducive to smelting that requires high-temperature slagging processes.
The melting furnace is divided into high frequency, intermediate frequency and power frequency.
(1) High-frequency melting furnace
The capacity of the high-frequency furnace is generally below 50 kg, which is suitable for smelting special steel and special alloys in laboratories and small-scale production.
(2) Intermediate frequency melting furnace
The capacity and power of the intermediate frequency smelting furnace are larger than that of the high frequency furnace. Mainly used for smelting special steels, magnetic alloys and copper alloys. Because this kind of furnace requires expensive frequency conversion equipment, it has been switched to a power frequency coreless furnace in some larger capacity occasions. However, compared with the industrial frequency furnace, the intermediate frequency furnace also has its own unique features. For example, for the furnace of the same capacity, the input power of the intermediate frequency furnace is larger than that of the industrial frequency furnace, so the melting speed is faster. The intermediate frequency furnace does not need to lift the furnace block when the cold furnace starts to melt. The molten metal can be poured out, so the use is more The power frequency furnace is flexible and convenient; in addition, the solution in the intermediate frequency smelting furnace has a lighter scour on the crucible, which is beneficial to the furnace lining. Therefore, after the development of high-power and cheap intermediate frequency power supplies, intermediate frequency furnaces are still promising.
(3) Power frequency melting furnace
The power frequency smelting furnace is the latest and the fastest developing among several smelting furnaces. It is mainly used for the smelting of cast iron and steel, especially high-strength cast iron and alloy cast iron, as well as the heating, heat preservation and composition adjustment of the cast iron solution; in addition, it is also used for the smelting of non-ferrous metals such as copper and aluminum and their alloys. If the furnace capacity is small, it is not economical to use power frequency. Take cast iron as an example. When the capacity is less than 750 kg, the electrical efficiency will decrease significantly. Vacuum induction melting furnace is used to melt heat-resistant alloys, magnetic alloys, electrical alloys and high-strength steels. The characteristic of this furnace type is that it is easier to control the furnace temperature, vacuum degree and melting time during the melting process, so the degassing of the charge can be very sufficient. In addition, the addition amount of alloy material can also be accurately controlled, so it is a more suitable furnace for smelting heat-resistant alloys and precision alloys containing active elements such as aluminum and titanium