I. Technical Principle and Core Components
1. Working Principle
Based on electromagnetic induction heating technology: A high-frequency power supply (30-100kHz) generates an alternating magnetic field in the induction coil. When a metal workpiece is placed inside the coil, eddy current effects and hysteresis loss within the workpiece convert electrical energy into heat, enabling rapid heating. This technology features high efficiency (≥90%), precise temperature control (±5ºC), and excellent heating uniformity, making it ideal for strict temperature gradient and phase transformation requirements in metal heat treatment.
2. Key Components
- High-Frequency Power Supply: Outputs 25kW power, using IGBT or MOSFET power devices to convert mains power into high-frequency alternating current, determining heating speed and stability.
- Induction Coil: Customized for workpiece shapes (e.g., loop, planar), typically made of copper tubes with water cooling; magnetic field distribution directly affects heating area and efficiency.
- Control System: Integrated with PLC or touchscreen, supporting multi-parameter presetting (temperature, time, power); some models offer PID intelligent temperature control and data logging (e.g., heating curve storage).
- Cooling System: Predominantly water-cooled (requiring a cooling tower or circulation tank); some portable models use air cooling + built-in water tank to prevent overheating of the power supply and coil.
II. Application Scenarios and Process Advantages in Metal Heat Treatment
1. Typical Applications
| Process Type |
Application Cases |
Technical Value of the Equipment |
| Surface Hardening |
Gear tooth surfaces, bearing raceways |
Rapid heating (10-30s) for surface hardening while maintaining core toughness |
| Annealing/Tempering |
Mold stress relief, spring tempering |
Uniform heating (temperature fluctuation ≤10ºC) to avoid deformation and cracking |
| Through Heating for Forging |
Bolt and shaft blank preheating |
Deep heating (for workpieces with diameter 10-50mm) to improve forging plasticity |
| Welding Preheating |
Copper tube brazing, tool shank welding |
Localized precise heating (heating zone ±2mm) to reduce the heat-affected zone |
2. Advantages Over Traditional Heating Methods
- Efficiency Improvement: 3-5 times faster than box furnaces; a 25kW device can process approximately 500kg of workpieces per hour (e.g., quenching φ20mm shafts).
- Energy Saving: 40% higher power efficiency than gas furnaces; intelligent temperature control avoids "idle heating," suitable for large-scale energy-saving production.
- Environmental Friendliness: No open flame or excessive fumes, compliant with ISO 14001 environmental standards, ideal for high-demand workshop environments.
- Flexible Production: Coils can be quickly replaced to adapt to different workpiece sizes (5-100mm diameter), enabling easy switching for small-batch, multi-variety production.
III. Key Technical Parameters and Selection Considerations
1. Detailed Core Parameters
- Power Density: 25kW corresponds to ~1-2kW/cm² (depending on coil design); higher power density enables faster heating (e.g., heating a 10mm steel plate to 850ºC in 20s).
- Frequency Range: 30-80kHz high frequency, suitable for heating depths of 0.5-5mm (e.g., surface hardening); lower frequencies (10-30kHz) are preferred for deeper heating (>5mm).
- Duty Cycle: Most models reach 99% (e.g., HT-25A series), supporting 24/7 continuous production, ideal for batch heat treatment lines in automotive parts.
- Dimensions and Weight: Conventional models: ~500×400×600mm (e.g., CH-25KW), 60-80kg; portable models (e.g., DW-25KW): 400×250×270mm, 19kg, suitable for on-site maintenance.
2. Key Selection Factors
- Workpiece Material: Carbon steel (high heating efficiency), stainless steel (requires higher power), aluminum alloys (needs specialized coil design); material magnetic permeability affects heating speed.
- Heating Depth: Choose high frequency (30-100kHz) for surface hardening and medium frequency (1-10kHz) for through heating, matching the equipment frequency to requirements.
- Production Beat: Continuous lines need high-duty-cycle models, while intermittent production can use standard models to reduce costs.
IV. Industry Application Cases and Benefit Analysis
1. Automotive Components Industry
- Scenario: A gearbox factory uses a 25kW high-frequency device (60kHz) with a contoured coil for gear tooth surface hardening. Heating time is reduced from 5 minutes (traditional salt bath furnace) to 20 seconds, energy consumption decreases by 55%, and the hardened layer depth is uniform (0.8-1.2mm) with hardness HRC58-62, meeting ISO 6336 standards.
2. Hardware Tools Industry
- Scenario: A cutting tool factory anneals high-speed steel drills using a 25kW device (temperature controlled at 780ºC±5ºC). Heating uniformity improves by 30% compared to box furnaces, tool hardness variation after annealing is ≤2HRC, and the scrap rate drops from 8% to 1.5%, saving approximately CNY 120,000 annually.
V. Equipment Maintenance and Safety Specifications
- Routine Maintenance: Check cooling system water quality weekly (conductivity <50μS/cm), clean coil surface oxidation monthly, and calibrate temperature sensors quarterly.
- Safety Requirements: Equip with ground protection (ground resistance <4Ω), set up electromagnetic radiation shielding in operation areas (field strength <2mG), and require operators to wear anti-radiation gloves and goggles.
VI. Industry Development Trends
- Intelligence: Integration of AI algorithms to automatically optimize heating parameters based on workpiece materials (e.g., FANUC's iH induction heating system).
- Modularity: Modular design of coils and power supplies supports quick replacement for customized production (e.g., Inductoheat's ModulLine series in Germany).
- Greenization: Matching with photovoltaic power systems to achieve "zero-carbon heating," compliant with EU CE certification energy efficiency requirements (ERP Lot 21 standard).
With its high efficiency, precision, and environmental friendliness, 25kW high-frequency induction heating equipment has become the mainstream technology in metal heat treatment. Especially in high-end manufacturing sectors like automotive, aerospace, and molds, it is gradually replacing traditional heating methods, driving industry upgrading toward intelligence and greenization.
Audited Supplier 
){kind=link}