In the global steel recycling, foundry production and steel mill upgrading projects, the medium-frequency induction melting furnace has become one of the most widely used core thermal equipment, thanks to its high thermal efficiency, stable melting performance, low harmonic interference and strong adaptability to various scrap materials. For medium and large-scale metal melting enterprises, a stable, energy-saving and highly reliable 25-ton induction furnace system can directly improve hourly output, reduce unit power consumption, extend equipment service life and lower overall operating costs. This article systematically introduces a mature 25t high-efficiency energy-saving induction furnace solution, including overall design, core parameters, system composition, structural advantages, operating conditions, safety standards, technical services and application value, to provide a clear reference for steel melting project planning and equipment selection.
1. Overall Technical Design & System Configuration
This 25t induction melting furnace system adopts a mature and widely verified industrial configuration: one power supply unit with two furnace bodies. Under this layout, one furnace body carries out continuous melting production, while the other can perform lining construction, maintenance or standby, which greatly improves production continuity and equipment utilization, and avoids long-term shutdown caused by single furnace maintenance.
In terms of system matching, the whole line uses a single 24-pulse rectifier transformer to ensure low grid harmonics and stable power quality; both the electrical cabinet and furnace body adopt closed-loop plate heat exchanger cooling, which effectively controls temperature rise and reduces scaling and blockage risks. The furnace switching function is realized by an electric furnace change switch, which is safe, fast and reliable. The feeding mode adopts a hydraulic feeding trolley installed on the operating platform, which is stable and efficient; the tapping system uses hydraulic tilting furnace structure, matching with special tapping ladle to ensure smooth and safe steel discharge. The whole equipment supports local operation plus remote PLC control console, which realizes intelligent monitoring, parameter adjustment and fault alarm, making operation more standardized and safer.
The complete system mainly includes: high-voltage power supply module, 24-pulse rectifier transformer, medium-frequency power cabinet, resonant capacitor bank, two sets of 25t induction furnace bodies, hydraulic tilting system, electric furnace change switch, PLC control and monitoring system, closed-loop water cooling system, as well as complete protection devices and standard spare parts.
2. Core Performance Parameters
This series of 25t induction furnace is designed according to industrial heavy-duty working conditions, with stable performance and sufficient power reserve, which can meet long-cycle and high-load continuous production.
Basic Melting Parameters
- Rated capacity: 25 tons
- Maximum tapping weight: 30 tons (depending on lining condition)
- Rated tapping temperature: 1650 ℃
- Tap-to-tap cycle: 100 ±10% minutes
- Melting rate: 18 tons/hour
- Unit power consumption: ≈530 kW·h per ton of steel
Medium-Frequency Power System
- Rated power: 12,000 kW
- Input voltage: 1500 V
- Rectification mode: 24 pulses
- Operating frequency: 250 Hz
- Output voltage: 5000 V
- Power factor: ≥0.95 under full load
Furnace Body Structure
- Inductor inner diameter: Φ1830 mm
- Inductor height: 2460 mm
- Inductor working voltage: 5000 V
- Cooling mode: closed circuit, pressure 0.25–0.3 MPa
- Cooling water flow: 450 t/h
- Inlet water temperature: ≤40 ℃
- Allowable temperature rise: ≤12 ℃
Hydraulic System
- Working pressure: 12 MPa
- Hydraulic medium: N46/N68 anti-wear hydraulic oil
- Tilting cylinder diameter: Φ250 mm
- Maximum safe tilting angle: ≤95°
Rectifier Transformer
- Rated capacity: 14,000 kVA
- Primary voltage: 11 kV
- Secondary voltage: 1500 V
- Impedance voltage: >10%
- Cooling mode: forced oil water cooling
- Water circulation: closed internal and external double loop
All the above parameters are tested under standard working conditions, including reasonable scrap ratio, continuous hot melting, sufficient charging, normal lining condition and stable water and electricity supply.
3. Applicable Materials & Standard Working Conditions
This 25t induction melting system has strong material adaptability and can stably melt most ferrous metals and recycled scrap materials. It is suitable for carbon steel, alloy steel, stainless steel, cast iron, scrap iron, steel shavings, briquetted light scrap, bundled thin material, cut heavy scrap and various recycled metal blocks after pressing. For enterprises with metal recycling, pressing and melting integrated production line, this equipment can form a highly efficient production chain with metal balers, shears, conveying and feeding systems.
To ensure the equipment reaches nominal output and power consumption indicators, the following standard working conditions are recommended: tapping temperature not higher than 1650 ℃; auxiliary time such as initial feeding and tapping controlled within 8 minutes; scrap yield ≥98%; light and thin materials pressed into blocks, large materials cut properly, with pressing manipulator assistance; melting process keeps hot state and continuous operation; furnace charge is full with material height 200mm above furnace mouth; lining built with standard crucible mode, and tested in the middle furnace campaign period; heat preservation and slagging time are not included in the melting cycle, and actual molten steel weighing shall prevail.
In terms of environment, the equipment is suitable for installation at altitude ≤2000m, ambient temperature 0–50 ℃, relative humidity ≤90%, no conductive dust, no explosive or strong corrosive gas, no obvious vibration, and seismic intensity ≤8 degrees. Power supply shall meet three-phase voltage imbalance <2%, voltage fluctuation <±5%, waveform distortion rate <3%, so as to ensure stable operation of medium-frequency power supply. For closed double-loop cooling system, internal circulation water must reach demineralized water standard, with conductivity <20 μs/cm, to avoid coil scaling and insulation degradation.
4. Structural Advantages & Core Component Features
The overall design of this 25t induction furnace focuses on stability, energy saving and durability, with many optimized structures to improve performance and reduce failure rate.
The furnace body adopts energy-saving flat-winding inductor with copper tube wall thickness ≥8mm, which has high conductivity, strong mechanical strength and good heat resistance, effectively reducing magnetic leakage and improving energy utilization. The magnetic yoke uses high-quality silicon steel sheet, with uniform magnetic field distribution, reducing local overheating and noise. The furnace body structure is heavy-duty welded steel part with high rigidity and strong load capacity, supporting long-term heavy-duty operation. The tilting cylinder and hydraulic system provide stable pressure output, with smooth action, no impact, and equipped with mechanical limit and electrical limit dual protection to avoid over-tilting.
The medium-frequency power cabinet adopts 24-pulse rectification technology, which significantly reduces harmonic interference to the power grid and improves power factor, helping enterprises reduce electricity costs and meet grid access requirements. The internal core components such as SCR, diode and capacitor adopt industrial-grade high-stability parts, supporting high current and high voltage working conditions. The control system is based on PLC platform, with automatic and manual dual modes, real-time data display, fault self-diagnosis, alarm recording and historical query functions, which makes operation and maintenance more intuitive and efficient.
The closed-loop water cooling system uses plate heat exchanger with high heat exchange efficiency, clean internal circulation water quality, stable temperature control, effectively extending the service life of induction coil, capacitor, cable and power components, and reducing daily maintenance workload. The whole equipment is equipped with leakage alarm, water flow / pressure / temperature monitoring, overcurrent, overvoltage, phase loss, emergency stop and interlock protection, forming a full-dimensional safety protection system.
5. Safety Operation & Maintenance Requirements
As high-power and high-temperature thermal equipment, the 25t induction furnace must follow strict safety specifications and maintenance rules to ensure long-term safe and stable operation.
During daily use, it is forbidden to run the equipment with faults or perform live maintenance. The maximum tilting angle of furnace body shall not exceed 95°, and the limit switch must be checked regularly to avoid bracket collision or fracture. All rotating parts need periodic inspection and lubrication (usually 7–14 days) to prevent shaft seizure. The coil casting slurry and lining materials should be supplied by professional manufacturers, and professional construction is recommended to ensure lining safety and service life. When replacing coil casting slurry, the inductor coil shall be re-insulated and wrapped, and uneven inter-turn spacing shall be repaired. Flushing the lining with water during dismantling or building is strictly prohibited.
In addition, the capacitor bank needs forced air cooling with wind speed ≥4m/s and ambient temperature ≤45 ℃. For flammable, explosive and sealed containers, it is strictly forbidden to mix them into scrap. During temperature measurement and sampling of molten steel, the intermediate frequency output voltage shall be reduced to below 800V to ensure operational safety. Since this equipment is high-power and large-capacity, compact production rhythm, timely feeding and continuous melting are helpful to reduce no-load power loss, improve output and reduce unit energy consumption.
6. Compliance & Implementation Standards
This series of induction furnace is designed and manufactured in strict accordance with current national and industrial standards, covering safety, performance, test method, energy consumption, power quality and other dimensions, including but not limited to:
- GB/T 10067.3 Basic technical requirements for induction electroheat installations
- GB/T 10066.3 Test methods for coreless induction furnaces
- GB 5959.1–3 Safety requirements for electroheat installations
- JB/T 4280 Medium-frequency coreless induction furnace
- GB/T 14549 Power quality – harmonics in public supply network
- GB 50060 Code for design of 3–110kV high voltage power distribution equipment
- JB/T 10358 Water-cooled cables for industrial electroheat installations
Compliance with these standards ensures that the equipment has high safety, reliability and power quality, and can adapt to inspection and acceptance requirements in domestic and overseas industrial projects.
7. Typical Supply Scope & Optional Equipment
The standard complete delivery scope of this 25t induction furnace system includes: two sets of 25t furnace bodies, medium-frequency power cabinets, oil-immersed reactor, capacitor bank, electric furnace change switch, hydraulic system, PLC control system, leakage alarm device, crucible mold, water-cooled cables and busbars, as well as a full set of free commissioning spare parts (including main control board, pulse board, SCR chip, fuse, switch power, meters, buttons, resistors, capacitors, potentiometers, transformers, etc.).
Optional auxiliary equipment can be configured according to project needs: 24-pulse rectifier transformer, low-voltage distribution cabinet, 300t/h and 450t/h plate heat exchangers with pump and control, installation materials, power and control cables, and shipping service to the designated port.
8. Technical Service & After-Sales Support
To ensure smooth installation, commissioning and long-term stable operation of the equipment, a complete set of technical and after-sales support is provided:
- On-site installation guidance and commissioning until qualified acceptance
- Free operation and maintenance training for the buyer’s staff
- Quick response: within 6 hours after receiving maintenance demand
- On-site service available within 48 hours
- Long-term stable supply of spare parts at preferential prices
- Warranty protection for key electrical and hydraulic components
For overseas projects, the buyer shall provide accommodation, visa, round-trip tickets and subsidy for technicians. Professional training covers equipment principle, operation process, daily maintenance, common fault diagnosis and safety operation rules, so that operators can use the equipment skillfully and maintenance personnel can handle routine problems independently.
9. Application Value & Enterprise Benefits
For steel mills, scrap recycling bases, foundries and metal processing enterprises, this 25t high-efficiency energy-saving induction furnace brings comprehensive value improvement. The mature one-power two-furnace configuration greatly improves production continuity; high melting rate and low power consumption directly reduce per-ton production cost; heavy-duty structure and high-standard configuration reduce failure rate and downtime; intelligent PLC control lowers labor intensity and improves operation stability; complete safety design and after-sales service reduce operational risk.
Whether it is a new melting project, production line expansion or old equipment upgrading, this solution can provide stable output, low energy consumption and long-life service for enterprises, with high cost-performance ratio and strong return on investment.
Conclusion
The 25t high-efficiency energy-saving induction furnace is a mature, reliable and practical solution for medium and large-scale steel melting projects. With reasonable configuration, standard operation and professional maintenance, it can adapt to various scrap materials and working conditions, and help enterprises achieve high efficiency, energy saving, safety and stable production. For global metal recycling, steelmaking and foundry enterprises, this equipment is an ideal choice to improve productivity, reduce costs and enhance market competitiveness.
