Last updated on April 18th, 2024 at 02:24 am

Induction heating is a safe, non-contact, and meticulous process for heating electrically-conductive materials like steel, graphite, copper, brass, silver, gold, aluminium, and carbide. It involves a complex amalgamation of electromagnetic energy and heat transfer through an induction coil, melting down materials and creating an electromagnetic field. This process is used for various applications, including hardening, annealing, tempering, brazing, and soldering.

Pros of induction heaters

• Induction heating is precise and useful in surface hardening of metals and non-ferrous metals, since the heat can be confined to the surface of the part.
• The process is carried out without making any direct contact to the power supply.
• The working conditions are satisfying as there is no noise, dust or smoke produced during its operation.
• It is most suitable for production of high-grade alloys.
• Presence of skilled labour is not a necessity, thus it reduces the operating cost.

Cons of induction heaters

• Initially, the process requires high capital investment.
• The process is restricted to a few materials.
• The heating is done in a non-uniform manner.
• The corners of the work-piece get more heat than the other parts.

How to choose induction heaters for industrial use?

Selecting the right induction heater depends on your application and requirements. Overpowered systems can increase costs, while underpowered ones slow down production and lengthen the heating process. Consider these factors when choosing the right system. 

1. Your part’s material

 Induction heats conductive materials like metals directly, while non-conductive materials are heated with a conductive susceptor. Magnetic materials are more easily heated, requiring more power. High-resistivity metals like steel heat quickly, while low-resistivity metals require more time. 

2. Depth of heating penetration

Over 80% of heat produced in parts is on the skin, requiring longer heating times for larger, thorough parts compared to thin or small ones.

3. Operating frequency

Lower-frequency, advanced-power systems are ideal for larger parts, while higher-frequency systems are suitable for surfaces, with higher frequencies causing shallower heating.

4. The power applied

Induction heating power supply output power determines part heating speed, considering mass, temperature rise, and heat losses. Induction equipment manufacturers can assist in evaluating these factors.

5. Rise in the required temperature

Induction generates significant temperature changes, but more power is needed to maintain them, affecting power-supply choices. The rate of temperature change also impacts power requirements.

6. Design of the coil 

The coil should follow the part’s shape and process variables, typically made of copper. An optimal design ensures the right heat pattern is delivered efficiently, while an ill-conceived coil slows down the process. Flexible coils are now available for large parts and unique geometries.

7. Coupling efficiency

Coupling a part with a coil increases current flow, generating more heat and increasing manufacturing efficiency. Poor coupling can have the opposite effect.

Which industries use induction heating?

Induction heating has been useful in heating liquid conductors and also gaseous conductors. It is often used to heat graphite crucibles and is used highly in the semiconductor industry for heating silicon and other semiconductors. 

Furnace: Induction furnaces use high-frequency magnetic fields to heat metal to its melting point, producing specialty steels and alloys in vacuum or inert atmospheres. They are used in modern foundries as a cleaner method than reverberatory furnaces or cupolas.

Welding: Induction welding is a small-scale process for welded plastics doped with ferromagnetic ceramics or metallic particles. It heats tubes’ seams, forcing them together and achieving high temperatures. RF current can be conveyed by brushes, heating the open seam.

Manufacturing: Rapid Induction Printing is a metal additive process that uses induction heating to create three-dimensional metal structures. It uses conductive wire feedstock and shielding gas, resulting in increased energy and material efficiency. This method offers higher safety compared to selective laser sintering.

Cooking: Induction cooking uses magnetic induction to heat cookware’s iron base, ensuring safety, efficiency, and speed, but is unsuitable for non-ferrous pans like copper-bottomed and aluminium.

Brazing: Induction brazing is a common technique in higher production runs, producing uniform and repeatable results in various industrial equipment, such as carbide brazing to shafts.

Sealing: Induction heating is utilised in cap sealing in food and pharmaceutical industries. It involves placing aluminium foil over the opening of a bottle or jar, heating it to fuse it, ensuring a tamper-resistant seal. 

Heat treatment: Induction heating is a widely used method for metal treatment, including steel hardening, soldering/brazing, and selective softening. It produces high-power densities and short interaction times, enabling the production of parts with varying properties. Controlling induction hardened patterns is possible through frequency, power density, and interaction time.

Plastic processing: Induction heating enhances energy efficiency in plastic injection moulding machines by generating heat directly in the barrel, reducing warm-up time and energy consumption. The coil can be placed outside. 

Benefits of induction heating for industries

1. Energy efficiency

Induction heating is a highly efficient heating process that uses less power to heat the same amount of material, making it up to 50% more efficient than other methods. This results in significant energy savings.

2. Heats only the target area 

Induction heating only heats the target area, as the electromagnetic field generated by the induction heater only penetrates the surface of the material being heated, ensuring no heat is lost to the surrounding area. This makes it ideal for applications requiring precise heating, such as in the medical industry.

3. Safe and clean

Induction heating is also safe and clean, with no open flames or hot surfaces, making it suitable for use in areas with flammable materials. It does not produce harmful emissions, making it an environmentally friendly option.

4. Pollution-free

Induction heating is also pollution-free, as most modern heating options produce some pollution. This is one of the key reasons why induction heating is preferred over other methods.

5. Fast heating method

The heating speed is another significant advantage of induction heating. The electromagnetic field generated by the induction heater can heat the material quickly and can be turned on and off quickly, making it ideal for applications requiring rapid heating.

6. Portable

Induction heating revolutionised the heating industry by making it mobile and requiring only an induction heater and power source for heating. This change made heating more accessible and accessible.

Conclusion 

To conclude, induction heating is a safe, non-contact, and meticulous process for heating electrically-conductive materials. Induction heating is precise and useful in surface hardening of metals and non-ferrous metals. The process is carried out without making any direct contact to the power supply.

Initially, the process requires high capital investment. Selecting the right induction heater depends on your application and requirements. Overpowered systems can increase costs, while underpowered ones slow down production and lengthen the heating process. Induction heating has been useful in heating liquid conductors and also gaseous conductors. Also, there are several benefits of induction heating as highlighted above. 

Many industries use Wattco products to achieve their environmental, economic, and production goals. Contact us to discover which products will best help your application and how we can customize it to meet your needs.