Technical Information

What is a medium frequency induction furnace? What is the use of?

Author : admin Time: 2023-09-01

Steel Shell Induction Furance_副本

Medium frequency induction furnace

Medium-frequency induction furnace is a kind of three-phase power frequency alternating current, rectified into direct current, and then direct current into adjustable current, supplying the alternating current flowing through the capacitor and induction coil, High-density magnetic field lines are generated in the induction coil, cutting the metal material contained in the induction coil, and generating large eddy currents in the metal material. This eddy current also has some properties of medium-frequency current, that is, the free electrons of the metal itself generate heat when flowing in a resistive metal body.

Product introduction

For example, a metal cylinder is placed in an induction coil with alternating medium-frequency current. The metal cylinder is not in direct contact with the induction coil. The temperature of the energized coil itself is already very low, but the surface of the cylinder is heated until it turns red or even melts. , and this redness and melting speed can be achieved by adjusting the frequency and the strength of the current. If the cylinder is placed in the center of the coil, the temperature around the cylinder will be the same, and the heating and melting of the cylinder will not produce harmful gases or strong light to pollute the environment.


Induction melting equipment series

Uses: Mainly used in smelting steel, iron, copper, aluminum and alloys, etc. It has the characteristics of high melting efficiency, good power saving effect, uniform metal composition, less burning loss, fast temperature rise, and easy temperature control. It is suitable for various metal smelting occasion. Features: Constant power output, faster melting speed and more obvious power saving effect. The zero-voltage frequency sweep software starts, which can better meet the requirements of frequent starts. Comprehensive protection measures, such as over-current, over-voltage, current limiting, pressure limiting, water shortage, and lack of protection, make the equipment run reliably under the premise of ensuring the melting speed. It is easy to operate and is suitable for various casting processes.

Induction heating equipment series

Application: Pre-forging heating: applied to the pre-forging heating process of gears, ring gears, half-shaft connecting rods, bearings, shackles, rigging and other products; online heating: pipeline anti-corrosion spraying, blue brittle blanking of bars, steel (wire) On-line quenching and tempering of pipes and other processes; local heating: U-bolt bending, roller thermal assembly, steel pipe bending and other production heating processes. Features: Simple production operation, flexible feeding and discharging, high degree of automation; Fast heating of workpieces, less oxidation and decarburization, high efficiency, good quality of forgings; Precise control of workpiece heating length, speed, temperature, etc.; Uniform heating of workpieces, temperature difference between core and surface Small size, high control precision; Inductor furnace integrated design, different inductors are designed with quick-change joints, easy to replace; All-round energy-saving optimization design, low energy consumption, high efficiency, lower production cost than coal-fired production; Environmentally friendly To standard, less pollution, but also reduce the labor intensity of workers.

Induction conditioning equipment series

The induction quenching and tempering production line equipment is based on the successful experience accumulated by our company in induction heating for several years, and a set of relatively high performance and price solutions are selected according to the process requirements of each product. The mechanical transmission device of the production line equipment adopts a single station mode, and the intermediate frequency quenching, intermediate frequency tempering and annealing are carried out according to the process and time. The replacement of the sensor adopts the method of overall hoisting, quick positioning, and quick connection of water and electricity (the replacement of a set of sensors can be completed in a short time). And the axis position of the sensor can be adjusted conveniently to meet the heating requirements of various billet specifications. According to the needs of each product, this set of equipment consists of the storage bracket for the incoming and outgoing materials, the conveying device for the incoming and outgoing materials, the rotating roller table transmission device for the workpiece, the intermediate frequency quenching and heating module, the intermediate frequency quenching and heat preservation module, the intermediate frequency tempering module, the intermediate frequency annealing module, It consists of 11 parts including quenching spray device, hydraulic station, center console and automatic control system.



1. Cooling water system Intermediate frequency power supply, induction coil, water cable, etc. all need water for cooling, so water is very important for furnace equipment. The probability of furnace equipment damage due to cooling water failure is high. Because most of the devices to be cooled are electrically charged objects, such as thyristors, induction coils, water cables, etc., the conductivity of the cooling water used to directly cool these devices must be lower than the specified value, and the connecting hose must be a carbon-free rubber hose. In addition, the inlet water temperature, outlet water temperature, water pressure and flow rate of cooling water must meet the design requirements. The cooling water system of the electric furnace is equipped with various sensors to monitor the relevant parameters of the cooling water. When the cooling water parameters are abnormal or exceed the set value, it will alarm or stop the operation of the equipment. The cooling water pumping station of the intermediate frequency electric furnace must be equipped with two main water pumps of the same specification (one for use and one for standby), and must be equipped with an emergency cooling water system. When the power supply of the grid is interrupted and the main water pump cannot work, the emergency cooling water system can provide cooling for the furnace body to avoid damage to the furnace body. 

2. Hydraulic system The hydraulic system of the intermediate frequency coreless induction furnace is used for pouring out the molten metal and opening and closing the furnace cover. In order to ensure reliable operation, the hydraulic station of the electric furnace should be equipped with two main pumps of the same specification (one for use and one for standby). The inlet end of the tilting furnace hydraulic cylinder needs to be equipped with a throttle valve to prevent the furnace body from falling suddenly due to the pressure loss of the hydraulic system. When the grid power supply is interrupted for a long time, the molten metal in the electric furnace may cool and solidify. This situation may damage the furnace lining. It is very dangerous to operate the electric furnace to melt the metal solidified in the furnace. Therefore, the electric furnace The hydraulic system should be equipped with an emergency system. When the grid power supply is interrupted, if necessary, the emergency system can be used to pour out the molten metal in the furnace to avoid freezing in the furnace. 

3. Ground leakage furnace monitoring and alarm: During the operation of the coreless medium frequency induction furnace, if the furnace lining is damaged, it will cause a furnace leakage accident. If molten metal leaks from the furnace lining, it will damage the insulation of the induction coil, the coil support and the magnetic yoke. If not detected in time, it will cause serious leakage. If the molten metal burns out the coil copper tube, the contact between the water in the tube and the molten metal may cause an explosion and cause a serious accident. It can be seen that it is completely necessary to set up a furnace lining leakage alarm system. A DC circuit can be connected in parallel to the AC power supply loop of the induction coil. The molten metal in the furnace is grounded through the furnace bottom electrode, and the induction coil is connected in series with the DC power supply and milliamp meter and grounded, so the molten metal, furnace lining, coil and milliamp meter are connected to form a DC loop. When the furnace lining is in good condition, because the resistance of the furnace lining is very large, the milliamp meter displays a very small value; if the furnace lining is in poor condition and molten metal penetrates into the furnace lining and approaches the induction coil, the resistance of the furnace lining will decrease, milliamps The indicated value of the meter becomes larger. When the current value exceeds the set value, an alarm will sound and the main power supply will be cut off, thus preventing furnace leakage accidents. 

4. Automatic fault diagnosis: Modern induction furnaces are equipped with computer management systems. This system has automatic fault diagnosis function. The system scans each set point of the equipment. When abnormal parameters of the set point are found, an alarm will be issued and fault information can be displayed and recorded. Because the scans are so fast, hundreds of times per minute, faults are discovered in their initial state before they cause serious equipment damage. Relevant information about the fault that occurred will be stored in the computer for future reference. In addition to the above, there are other safety measures. For example, when the door of the intermediate frequency power supply is opened, the incoming power supply will be automatically cut off through mechanical interlocking; When the pressure exceeds the set value, it will alarm and cut off the power supply to prevent the capacitor from exploding due to excessive internal pressure.

The main purpose

1)Hot forming: whole piece forging, local forging, hot heading, hot rolling; 

2)Metal melting: (vacuum) melting, casting molding and evaporation coating of gold, silver, copper, iron, aluminum and other metals; 

3)Heat treatment: partial or overall quenching, annealing, tempering, diathermy of various metals;

4)Other applications of high-frequency heating machine: semiconductor single crystal growth, heat fitting, bottle neck heat sealing, toothpaste skin heat sealing, powder coating, metal Implantation of plastics, etc;

5) Welding: brazing of various metal products, welding of various knife blades and saw blades, welding of steel pipes and copper pipes, welding of the same and different metals.

working principle

(1). The medium frequency induction electric furnace is composed of medium frequency induction electric furnace area, heat preservation area, front furnace, feeder, chimney and other main parts. The control part is mainly the combustion system and feeding system, and the operation process is controlled by programs. 

(2).Working process: Put aluminum alloy ingots or recycled materials (scrap aluminum parts with the same composition or similar composition, etc.) into the feeding trolley (about 300kg each time), and feed the aluminum in the feeding trolley through the feeder Alloy ingots or returned materials are put into the combustion chamber of the intermediate frequency induction furnace area to heat the intermediate frequency induction furnace. The waste gas and smoke generated during the intermediate frequency induction furnace process are discharged through the chimney. It flows into the lower heat preservation area, where the aluminum liquid is raised to the specified temperature and kept warm. Open the furnace door in the heat preservation area to refine, degas, and remove slag from the molten aluminum, purify the molten aluminum, and keep the temperature of the molten aluminum within the set aluminum tapping temperature range. The molten aluminum enters the forehearth through the overflow dam at the bottom of the heat preservation area, and the molten aluminum can be released through the aluminum outlet of the forehearth.

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