To obtain a flux diverter capable of obtaining a sufficient cooling effect without any failures and without generating any problems due to insufficient cooling for silicon steel plates by attracting the magnetic flux in the end surface, laminating silicon steel plates attached for compensating heat loss with reinforcing plates and directly applying water cooling with a stainless water pipe from the upper part of laminated silicon steel plates at the time of heating a billet in the low frequency induction heating furnace used in hot extruding.

This device is composed of the stainless pipe 13 for the cooling water pipe, silicon steel plates 14 attracting the magnet flux in the end surface at the time of heating the billet and compensating heat loss and reinforcing plates 15 reinforcing silicon steel plates 14. The stainless pipe 13 for the cooling water pipe and silicon steel plates 14 are directly connected by welding. By this way, silicon steel plates 14 are affected with cooling by the cooling water pipe. Reinforcing plates 15 are inserted between silicon steel plates 14 so that silicon steel plates do not strain.