What is the working principle of an intermediate-frequency furnace?
2022-02-08
A medium-frequency furnace is a power device that converts 50-Hz industrial-frequency AC into medium-frequency current (ranging from over 300 Hz to 1,000 Hz). It first rectifies three-phase industrial-frequency AC into DC, then inverts the DC into an adjustable medium-frequency current. This current flows through capacitors and induction coils, generating a high-density magnetic field within the induction circuit and inducing eddy currents in metallic materials placed inside the circuit, thereby heating or melting the metal.
What are the safe operating procedures for medium-frequency furnaces?
1. Precautions for the Furnace Area
Before turning on the medium-frequency furnace, inspect the electrical equipment, water-cooling system, sensor copper tubes, and other critical components. The furnace can only be activated if all these systems are functioning properly, ensuring safe heat treatment operations. Otherwise, the furnace must remain off. Designate a specific person responsible for electricity supply and furnace operation; this individual must not leave their post without authorization and should continuously monitor both the sensors and the external condition of the tungsten components during work hours. This precaution prevents anyone from coming into contact with sensors or cables after power has been supplied, thereby avoiding disruptions to the furnace’s normal operation or potential safety hazards.
II. Precautions After Turning On the Stove
When charging the medium-frequency furnace after it has been turned on, carefully inspect the furnace interior to ensure no flammable, explosive, or other hazardous materials are present. To prevent "lid formation," never add cold materials or moisture directly into the molten steel. Additionally, avoid introducing large, bulky chunks once the melt has already filled the upper portion of the furnace. To minimize the risk of explosions, make sure the fueling area and the pit in front of the furnace are free of standing water and any obstructions. During pouring, two people must work together; any remaining molten steel should be poured only onto the designated area—disposal on the ground is strictly prohibited.
III. Precautions During Maintenance
When maintaining the medium-frequency electric furnace, ensure the medium-frequency generator room remains clean and strictly prohibit the accumulation of flammable or explosive materials. Promptly repair furnaces that have overheated during melting, and when replenishing the furnace, avoid mixing iron with iron oxide while ensuring the tungsten remains tightly compacted.
What is the working principle of an intermediate-frequency furnace?
The medium-frequency furnace primarily consists of electricity, an induction coil, and tungsten made from refractory materials housed within the induction coil. Inside is a metal crucible, which acts as the secondary winding of a transformer. When the induction coil is connected to an AC power source, it generates an alternating magnetic field. This magnetic field induces an electromotive force in the metal crucible—essentially "cutting" through the magnetic lines of flux. Since the crucible itself forms a complete, closed-loop circuit, the induced current flows continuously in a single, uninterrupted path around the crucible. As a result, the crucible not only develops an induced current but also heats up and melts due to the resistance encountered by this flowing current.
The medium-frequency electric furnace uses a medium-frequency power supply to generate a medium-frequency magnetic field, which induces eddy currents and heat within the magnetic material, thereby achieving the purpose of heating. This type of furnace employs a 200-Hz medium-frequency power source for induction heating, melting, and holding temperatures. Primarily designed for melting carbon steel, alloy steel, and special steels, it can also be used for melting and reheating non-ferrous metals such as copper and aluminum. The equipment boasts a compact design, lightweight construction, high efficiency, low power consumption, rapid heating and melting rates, and easy-to-control furnace temperatures—making it an ideal choice for highly productive applications.
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2025-09-17