Introduction to Vacuum Induction Melting Furnace
Application
Mainly used for the production of special alloy materials such as nickel based high-temperature alloys, titanium alloys, stainless steel, and ultra-high strength steel.
Suitable for research and production departments to melt and cast nickel based special steels, precision alloys, iron neodymium manganese, active metals, high-temperature alloys, hydrogen storage materials, magnetic materials, powder metallurgy, etc. under vacuum or protective atmosphere. It can achieve continuous feeding, automatic sampling and other processes in the vacuum melting process!
Working principle
Under vacuum conditions, the induction coil obtains induced current through the principle of electromagnetic induction, achieving the purpose of heating. Current passes through an electromagnetic coil surrounding a metal material at a certain frequency, and the changing current generates an induced magnetic field, which induces current inside the metal and generates a large amount of heat to heat the material. When the heat is relatively low, it can be used for processes such as vacuum induction heat treatment. When the heat is high, the generated heat is sufficient to melt the metal and prepare metal or alloy materials.
Heating element: Copper induction coil
Maximum temperature: 1800 degrees Celsius
Ultimate vacuum degree: 7x10-3Pa
Heating time: After vacuuming is completed, heating begins, and the metal usually reaches a molten state within 30 minutes
Melting process: feeding ->vacuuming ->melting with electricity ->refining ->casting
Equipment advantages and characteristics
1. Fast heating speed;
2. Adopting efficient power supply, with low heat loss and high heating efficiency;
3. The product has less surface oxidation and high quality;
4. Able to accurately control the content of product ingredients;
5. Simple and convenient operation.
Composition and structure of vacuum induction melting furnace
The furnace body adopts a vertical or horizontal structure, mainly composed of furnace shell, inductor, crucible, tilting furnace mechanism, ingot mold mechanism, power supply device, water cooling system, vacuum system, control system, etc. The furnace shell can be equipped with observation windows, temperature measurement, feeding, sampling, and compacting devices.
1. Furnace body
Built in alloy feeder. By rotating the feeder handwheel, it is possible to sequentially add materials to the molten metal in the crucible.
The furnace cover is equipped with an observation window for easy observation of the working conditions inside the furnace. Usually, a cover plate is used to cover the glass observation to avoid contamination by metal vapor deposits.
Pre sintered shaped crucibles can be placed inside the sensor, or crucibles can be pounded on the inner wall of the sensor. The refractory material used to manufacture crucibles is related to the type of metal being melted.
Made of high-quality high-temperature resistant materials, it has the characteristics of high strength, high temperature resistance, corrosion resistance, etc., and can withstand high temperature and high pressure.
Made of high-strength carbon steel, after acid pickling, phosphating, rust removal, and electrostatic spraying, it is beautiful and elegant.
Double layer air-cooled furnace shell with 2-4 built-in cooling fans to ensure that the surface temperature of the furnace shell is below 60 ℃
2. Induction heating system
Including power supply, induction coil, cooling system and other equipment, it can achieve precise temperature control and uniform heating.
The inductor that generates induced current for melting metal is located inside the furnace shell. The sensor is made of rectangular copper tube wrapped around it, and it is fixed on the electrode with two connectors, making it easy to assemble and disassemble.
3. Vacuum system
Mechanical pump+Roots pump+diffusion pump vacuum unit, with a working vacuum degree of up to 6 × 10 ^ (-3) Pa
Control system:
Including power supply system, PLC control system and other equipment, capable of achieving automated experiments and remote control.
4. Security system
Including smoke detectors, alarms and other equipment, it can ensure the safety of experiments.
Operation steps of vacuum melting furnace
Step 1: Add ingredients
1. Vacuum melted materials must undergo special cleaning treatment to remove surface dirt, grease, etc., and be baked to remove moisture. Overly complex castings and recycled materials should be cut off, and surface oxide scales and non-metallic objects should be removed.
2. The loading principle is to tighten the bottom and loosen the top, placing longer bars and complex shaped materials underneath, and filling the gaps tightly with small pieces of material. Place materials with regular shapes at the top of the crucible to prevent bridging during the melting process. Some granular materials can be piled up in the direction of the steel outlet.
3. The loading action should be light to avoid damaging the crucible and causing slag inclusion in the molten metal.
Step 2: Vacuumize
Start the two-stage rotary vane mechanical pump first to evacuate the furnace body. At the same time, power is supplied to the diffusion pump to start heating the diffusion pump oil. When the mechanical pump is evacuated to 15Pa and the diffusion pump has been heated for about 50 minutes, the mechanical pump valve can be closed and the diffusion pump valve can be opened to evacuate the furnace to the required high vacuum.
Step 3: Power on and melt
1. First, start the thyristor intermediate frequency power supply and gradually increase the working voltage of the inductor. Generally, a smaller power is always supplied at the beginning to avoid excessive power causing a sudden and sharp rise in furnace temperature, resulting in a significant decrease in vacuum degree due to a large amount of gas release in the furnace in a short period of time. Therefore, the general speed of power increase is based on not causing a significant decrease in vacuum degree.
The maximum power of the electric furnace should be limited by the maximum values of the intermediate frequency voltage and current.
Step 4: Refining
When alloy material needs to be added after the furnace charge is fully melted, the handwheel on the alloy feeder can be rotated. The alloy material falls into the feeding hopper, and by gently rotating the operating handle of the hopper with your hand, you can add the alloy material into the crucible at the desired speed.
When some alloy materials are added to the crucible, it is easy to cause sputtering. At this time, it is important to note that the speed of alloy addition should not be too fast. Sometimes, the method of "conjunctival addition" is even adopted, which is to reduce the power, slightly freeze the liquid surface, and then add the alloy material to reduce sputtering.
Step 5: Casting
At the end of refining, there is no need to cut off the power, and the crucible can be tilted to pour the molten metal into the ingot mold. Be careful not to pour molten metal outside the ingot mold.
Standard accessories for complete equipment
1 set of furnace body;
2. One control cabinet;
3. One set of induction heater (including graphite crucible);
4. One set of vacuum system;
Options
1. Induction heater (including graphite crucible)
2. Silicone sealing ring
3. Vacuum pump oil

We possess over 10,000 square meters of modern, company-owned factory space. Equipped with specialized electric furnace production lines and advanced manufacturing and testing equipment, the company boasts a self-developed R&D team and a comprehensive after-sales service department. Our products specialize in melting metals and alloys, particularly steel, and are extensively applied in sectors including casting, steelmaking, nickel-based alloys, high-temperature alloys, soft magnetic metals, powder metallurgy, and related fields.