The differences between high-frequency and medium-frequency melting furnace

The key differences between high-frequency and medium-frequency melting furnaces lie in their operating frequency, heating depth, and application scenarios. High-frequency furnaces (above 10kHz) are suitable for rapid heating and surface treatment of small parts, while medium-frequency furnaces (1-10kHz) are more suitable for deep heating of large parts and batch melting.

Operating Frequency and Heating Characteristics.

High-frequency furnaces: With a frequency range of ≥10kHz, they exhibit a significant current skin effect and a shallow heating depth (0.5-2mm), making them suitable for metal surface hardening, melting small workpieces (≤5kg), and precious metal processing.

Medium-frequency furnaces: With a frequency range of 1-10kHz, they offer a greater current penetration depth (for example, the skin depth of copper at 5kHz is approximately 2.3mm). They can heat larger workpieces (5kg to 60 tons) and are suitable for batch melting of steel, copper alloys, and other materials.

Temperature and Efficiency Performance. 

High-frequency furnaces: They can reach a maximum temperature of 2200°C (when used with a graphite crucible), but thermal efficiency in the high-temperature zone decreases rapidly with power consumption, resulting in low energy consumption per smelting operation (for example, melting 1kg of gold requires only 0.3kWh).

Medium-frequency furnaces: Their conventional upper temperature limit is approximately 2000°C. When using a magnesia crucible, their thermal efficiency remains stable at 70-75%, making them suitable for long-term continuous smelting operations.

Equipment Structure and Application Scenarios

 High-frequency furnaces: They are compact (e.g., 400×300×500mm), lightweight (35kg), and support 220V single-phase power, making them suitable for mobile applications such as laboratories and jewelry processing.

Medium-frequency furnaces: They require a three-phase power supply and cooling system, resulting in a complex structure (including power supply cabinets, capacitor banks, etc.), but offer high power density and meet the large-scale production needs of foundries and metallurgical enterprises.