Induction heating device for roll and induction heating method

Abstract

An induction heating device for heating a roll by induction heating so as to equalize the diameter of the roll, the device comprising: an induction heater; for moving the induction heater to a heating part, while keeping the induction heater away from the part to be heated Induction heater moving means for keeping the distance of the surface constant; power supply means for supplying electric power to the induction heater; and heat regulation means for adjusting the heat of the induction heater according to the heat required by the heating part. The heat regulating device includes a frequency control device for controlling the frequency of the electric energy supplied to the induction heater, and when the heat required for the heating part is large, the frequency control device adjusts the frequency of the electric energy to a high frequency in a predetermined frequency range, and When the heat required for the heating part is small, the frequency control device adjusts the frequency of the electric energy down. Preferably the frequency is adjusted in the range of 25 to 200 kHz.

Description

technical field [0001] The invention relates to an induction heating device and an induction heating method. More particularly, the present invention relates to an induction heating device and an induction heating method for local heating of rolls of a rolling mill. Background technique [0002] In general, during hot rolling, a temperature difference occurs between the portion of the roll in the roll width direction that is passed through by the rolled sheet and the portion of the roll in the roll width direction that is not passed by the rolled sheet. Therefore, the roll diameter in the roll width direction differs due to the difference in thermal expansion of the rolls. Therefore, a hot rolling mill using an induction heating device that locally heats the low-temperature portion of the roll in a non-contact state so that the thermal expansion of the roll is kept constant in the roll width direction has been developed, such as disclosed in JP2000-2...

AI Technical Summary

Problems solved by technology

As a result, the heat density decreases

Thus, the heating efficiency required to correct the thermal expansion of the rolls 1, 2 decreases

In addition, when the frequency is low, since the magnetic flux density in the core 62 tends to increase, the size of the induction heater 6 required to obtain a predetermined amount of heat increases accordingly.

[0009] (2) On the other hand, when the frequency of the electric energy supplied to the coil 61 is high, the high-frequency loss of the feeder increases, and the loss of the matching circuit including the core 62 and the voltage acting on the coil also increases.

Therefore, it is impossible to significantly reduce the size of the power supply unit 8'

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