Electromagnetic induction heating 02
Induction Heating Principle
Induction Heating surface quenching is a quenching method that uses the principle of electromagnetic induction to generate high density induction current on the surface layer of the workpiece, rapidly heating to austenite state, and then rapidly cooling to get martensite structure.When through a certain frequency alternating current (ac) induction coil, in its inside and outside will produce the same as the current changes in the frequency of the alternating magnetic field the metal artifacts into the induction coil, under the effect of magnetic field, the workpiece can produce the same as the frequency of induction coil in the induced current in the opposite direction Because of the induced current forms a closed loop, the workpiece surface is commonly referred to as eddy current The eddy current electrical energy into heat energy, rapid heating of the workpiece surface Eddy current mainly distributed in the surface of workpiece internal almost no current through, this phenomenon is called the surface effect and skin effectInduction heating is the use of skin effect, relying on the current thermal effect of the workpiece surface quickly heated to the quenching temperature of the induction ring with copper tube to do, through cooling water when the workpiece surface in the induction ring heated to a certain temperature, immediately cooling water, so that the surface layer to obtain martensite tissue induced electromotive force instantaneous value of.
Frequency selection induction heating frequency selection: according to the heat treatment and heating depth requirements of the selection of frequency, the higher the frequency of the heating depth is shallow high frequency (above 10KHz) heating depth of 0.5-2.5mm,Generally used for heating of small to medium sized parts, such as small modulus gear and small and medium-sized shaft parts intermediate frequency (1 ~ 10 KHZ) heating depth is 2 to 10 mm, usually used in large diameter axle and the big modulus gear heating (50 hz) power frequency heating hardened layer depth of 10-20 mm, generally used for large size parts diathermy, large diameter parts (more than 300 mm diameter, such as roll, etc.) of surface hardening.