induction heating service,induction heater,induction heating equipment and induction heating system are supplied by DaWei Induction Heating Machine Co.,Ltd
Induction heating is a form of non-contact heating for conductive materials, when alternating current flows in the induced coil, varying electromagnetic field is set up around the coil, circulating current(induced, current, eddy current) is generated in the workpiece(conductive material), heat is produced as the eddy current flows against the resitivity of the material.
Induction heating is a rapid ,clean, non-polluting heating form which can be used to heat metals or change the conductive material’s properties. The coil itself does not get hot and the heating effect is under controlled. The solid state transistor technology has made induction heating much easier,cost-effective heating for applications including soldering and induction brazing ,induction heat treating, induction melting,induction forging etc.<
Induction Heating is a flame-free, no-contact heating method that can turn a precisely defined section of a metal bar cherry red in seconds. How is this possible?
How Induction Heating works?
Alternating current flowing through an induction coil generates a magnetic field. The strength of the field varies in relation to the strength of the current passing through the coil. The field is concentrated in the area enclosed by the coil; while its magnitude depends on the strength of the current and the number of turns in the coil. (Fig. 1) Eddy currents are induced in any electrically conductive object—a metal bar, for example—placed inside the induction coil. The phenomenon of resistance generates heat in the area where the eddy currents are flowing. Increasing the strength of the magnetic field increases the heating effect. However, the total heating effect is also influenced by the magnetic properties of the object and the distance between it and the coil. (Fig. 2) The eddy currents create their own magnetic field that opposes the original field produced by the coil. This opposition prevents the original field from immediately penetrating to the center of the object enclosed by the coil. The eddy currents are most active close to the surface of the object being heated, but weaken considerably in strength towards the center. (Fig. 3) The distance from the surface of the heated object to the depth where current density drops to 37% is the penetration depth. This depth increases in correlation to decreases in frequency. It is therefore essential to select the correct frequency in order to achieve the desired penetration depth.