Induction heating is a highly efficient and fast method that uses a magnetic field to heat conductive materials, such as metals and semiconductors, without contact. This method has become increasingly popular for industrial, medical, and domestic applications due to its many advantages over traditional heating techniques, such as resistance, flame, and ovens/furnaces. Induction heating is beneficial for highly precise or repetitive operations, where consistent heating and temperature control are critical for the quality and repeatability of the end product.
In induction heating, an alternating current (AC) source is used to supply current to an induction heating coil. As a result, the coil generates an alternating magnetic field. When an object is placed in this field, two heating effects occur:
Both effects result in the heating of the treated object, but the second one is most commonly the main heat source in IH processes. Moreover, hysteresis is not observed in non-magnetic materials, and magnetic materials lose their magnetic specificities if heated above a specific temperature (the so-called Curie point).
Eddy currents also depend on the magnetic field frequency due to the skin effect – at high frequencies, the currents flow close to the conductor surface. This specificity is used to control the penetration depth of the induction heating process. As a result, either the whole object or only a specific part of it (only the surface, for example) can be heated. Thus, induction heating can be used for different applications – from metal melting to brazing and surface hardening.
Skin effect is also observed inside the induction coil conductor. Therefore, pipes can be used instead of solid wires. When the current flows through the inductor, similar resistive losses are observed due to the Joule effect. In order to prevent the coil from melting and damage, water cooling is often applied.
Compared to some of the classic heating techniques (resistance heating, flame heating, furnaces, etc.), induction heating has the following advantages:
Although induction heating systems have already reached maturity as a technology, the development of modern technologies continuously provides options for new research trends and industrial interest. In the coming years, the following topics are expected to be of significant interest:
Induction heating was first discovered by Michael Faraday as he studied the induction of currents in wires by a magnet. The fundamental principles of induction heating were later established and developed by James C. Maxwell in his unified theory of electromagnetism. James P. Joule was the first to describe the heating effect of a current flowing through a conductive material.
In 1887, Sebastian Z. de Ferranti proposed induction heating for metal melting and filed the first patent on the industrial applications of induction heating. The first fully-functional induction furnace was presented in 1891 by F. A. Kjellin, and the first high-frequency furnace application of induction heating was implemented by Edwin F. Northrup in 1916.
During the Second World War and afterward, the use of induction heating technology was boosted by the aircraft and automotive industries. Induction heating was not only used for metal melting but also for advanced material treatment, which significantly increased the range of induction heating applications.
The development of solid-state generators using new power semiconductor technologies provided the potential for IH beyond the industrial environment. Since the late 1980s, different domestic applications have appeared. In recent years, a particular interest in induction heating for medical treatments has emerged, as this method provides precise and targeted local heating.
Today, induction heating technology provides highly efficient and reliable systems for a wide variety of applications.
UltraFlex Power offers a free induction heating calculator to help you estimate your heating process parameters quickly.
References
Lucia, O., P. Maussion, E. J. Dede, J. Burdio, Induction Heating Technology and Its Applications: Past Developments, Current Technology, and Future Challenges, (2013) IEEE Transactions on Industrial Electronics, vol. 61 ( 5), pp. 2509-2520.
Tudbury, C. A., Basics of Induction Heating, vol. 1, J. F. Rider, May 1960, New York, US.
Magnet, Wikipedia article
https://en.wikipedia.org/wiki/Magnet#Magnetic_metallic_elementsJoule heating, Wikipedia article
https://en.wikipedia.org/wiki/Joule_heatingCurie temperature, Wikipedia article
https://en.wikipedia.org/wiki/Curie_temperatureWith high quality products and considerate service, we will work together with you to enhance your business and improve the efficiency. Please don't hesitate to contact us to get more details of Induction Forging Furnace For Steel Bars And Rods, induction forging furnace, medium frequency induction furnace.