What Is a Medium Frequency Induction Furnace?

A medium frequency induction furnace (MF furnace) refers to an induction melting system operating between 150 Hz and 10,000 Hz, with the most common industrial frequencies being 150 Hz, 1,000 Hz, and 2,500 Hz.

This furnace type is widely used for melting high-quality steel, alloy steel, copper, aluminum, and specialty materials.

In global applications, MF furnaces range from a few kilograms to several dozen tons. The world’s largest operating MF induction furnace reaches 20 tons, 4400 kW, 600 Hz.
In China, the largest industrial MF furnace is 3 tons, while most running units are 6-ton models.

Key Advantages of Medium Frequency Induction Furnaces

1. Faster Melting Speed & Higher Productivity

MF induction furnaces have higher power density, typically 20–30% more than power-frequency furnaces of the same size.
This results in:

• Higher melting efficiency
• Shorter cycle time
• Greater output per shift

This advantage is crucial for steelmaking plants requiring rapid turnover.

2. Strong Adaptability & Flexible Production

MF furnaces allow complete tapping of molten steel, enabling quick changes between different steel grades.
In contrast, power-frequency furnaces require residue metal for restart, limiting flexibility.

MF furnaces are ideal for:

• Multi-grade production
• Frequent material changeovers
• Small to medium batch flexible manufacturing

3. Optimal Electromagnetic Stirring

Electromagnetic force is inversely proportional to the square root of power frequency.
Medium frequency provides moderate, stable stirring, offering:

• Better removal of impurities
• More uniform chemical composition
• More uniform molten metal temperature
• Reduced refractory erosion compared to power-frequency furnaces

This leads to longer crucible life and better refining quality.

4. Easy Startup & Lower Energy Consumption

Because medium frequency current has a strong skin effect, it heats the charge easily without requiring special startup blocks.
Benefits include:

• Immediate heating after charging
• No need for cast-steel starting blocks
• Faster temperature rise
• Reduced electricity waste during periodic operation

Power-frequency furnaces, by contrast, require hand-made starter blocks and heat up much slower.

Typical Frequency & Power Configuration (Industrial Standards)

Industrial Applications

Medium frequency induction furnaces are widely used in:

• Steel & alloy melting
• Stainless steel refining
• Copper, brass, and aluminum melting
• Foundry and casting workshops
• Precision alloy manufacturing
• Metallurgical research institutions

Why MF Induction Furnaces Are Preferred Worldwide

MF technology is considered the optimal balance between:

• Melting speed
• Metallurgical quality
• Operational flexibility
• Energy efficiency
• Furnace longevity

This makes it the leading choice for modern foundries, steel mills, and alloy producers.