Differences between Medium-Frequency Furnaces and High-Frequency Furnaces

The core difference between high-frequency and medium-frequency furnaces lies in their operating frequency. High-frequency furnaces typically operate at frequencies above 10,000 Hz, providing rapid heating but shallow penetration, making them suitable for small parts, surface treatments, or low-melting-point metals. Medium-frequency furnaces operate between 50-2000 Hz, providing uniform heating and deep penetration, making them suitable for large-scale smelting or high-melting-point metals.

Core Principles and Heating Characteristics Differences

Operating Frequency: This is the most fundamental difference between the two types of equipment. High-frequency furnaces typically operate at frequencies above 10,000 Hz, reaching up to 1 MHz; while medium-frequency furnaces operate between 50 Hz and 2000 Hz, commonly between 300 Hz and 1000 Hz.

Heating Characteristics: The frequency difference directly leads to different heating methods. High-frequency furnaces utilize the strong skin effect, concentrating heat on the metal surface for extremely rapid heating, but with limited penetration depth, easily resulting in a situation where the surface melts while the core remains uncooked. Medium-frequency furnaces have stronger magnetic field penetration, enabling metal to be heated evenly from core to surface, resulting in a more stable and thorough heating process.

Typical Application Scenarios and Selection Criteria

Suitable Metal Types

High-frequency furnaces: More suitable for melting low-melting-point non-ferrous metals such as aluminum, copper, zinc, and magnesium, as well as precious metals such as gold and silver. Their rapid heating reduces oxidation losses at high temperatures.

Medium-frequency furnaces: More suitable for melting high-melting-point ferrous metals such as steel, iron, stainless steel, and high-temperature alloys. Their deep-penetration heating characteristics ensure uniform melting of the entire metal, avoiding undercooked metals.

Single Melting Capacity and Production Scale

High-frequency furnaces: Smaller capacity (usually below 50 kg), moderate power (10kW-50kW), small footprint, suitable for small-batch, multi-batch production in laboratories, small workshops, jewelry processing, etc. Medium-frequency furnaces: Larger capacity and power (commonly 5kg-500kg, 50kW-500kW), suitable for industrial applications requiring large-scale, continuous production, such as foundries and forging plants.

Different Emphasis on Metal Quality

High-frequency furnaces: Due to their rapid heating and small crucible volume, they reduce the contact time between metal and air, making them more suitable for applications requiring high metal purity and oxidation control, such as high-purity materials in the electronics industry and jewelry processing.

Medium-frequency furnaces: Heating is relatively slow and uniform, and the magnetic field stirs the molten metal, promoting component mixing, making them more suitable for applications requiring high uniformity of metal composition, such as structural steel casting.

Other Key Differences and Considerations、Equipment Scale and Supporting Facilities

High-frequency furnaces: Typically more compact, some models can use 220V household electricity, requiring less space and power supply. Medium-frequency furnace: Larger in size, requires 380V three-phase industrial power, and usually needs a cooling system (such as a cooling tower), placing higher demands on infrastructure.

Production rhythm and operating costs

High-frequency furnace: Quick start-up and shutdown, suitable for frequent changes in smelting materials and multi-variety, small-batch production.

Medium-frequency furnace: High thermal inertia, more suitable for long-term continuous operation, and may have lower energy consumption per unit weight of metal, but frequent start-ups and shutdowns increase losses.