Electromagnetic induction heating: technology

Induction heating is an electrothermal technique for heating electrically conductive materials without physical contact with an electrical source. The theoretical basis was explained in the previous article. This article looks at the problems encountered when setting up an installation, their solutions and the main industrial applications of this type of heating.

Given the special nature of the materials processed, it's hardly surprising that these applications are particularly relevant to metal metallurgy, whether for melting metals and alloys, for heating them prior to transformation or assembly, or for surface heat treatment. In 10 years, induction's share of electricity applications has risen from 2% to 5%, representing some 150 GWh.

The conquest of new markets launched induction into new sectors, in particular the chemical industry and the consumer market. Thanks to advances in electronics technology and the emergence of faster switching components, higher-frequency applications have been developed for non-metallic materials. Recent years have seen the emergence of highly innovative new applications, such as the direct fusion of glasses and oxides, or plasmas, with newly-designed appli-cators.

The engineer is therefore faced with an increasingly delicate process implementation, due to the presence of high currents, high voltages and high frequencies in the installations. What's more, the need to comply with electromagnetic compatibility standards means that they must be able to control the pollution created by the installation, either in the direction of the electrical network, or in the immediate environment.

The article "Electromagnetic induction heating" is the subject of two booklets:

D 5,935 Principles

D 5,936 Technology

The subjects are not independent of each other.

Readers will need to refer back to the other issues often enough.

Please also refer to the Notations and symbols table at the beginning of this article D 5 935 [1] .