PURPOSE: To facilitate the maintenance of a specified temperature of wound cores in each tank and to improve the magnetic characteristics of the wound cores consisting of an oxide amorphous magnetic material as well by a method wherein an annealing furnace main body is composed by adjoining heating tanks and cooling tanks through freely opened and closed partition plates and inactive gas is introduced in the heating tanks and the cooling tanks.

CONSTITUTION: An annealing furnace main body annealing wound iron cores 10 which are annealed materials is composed of two each of heating tanks 1, 2 and cooling tanks 3, 4 which are continuously arranged on a line and a pair of conductors 14 connected to an external DC power source 16 and short-circuited the faced end section with a removable connecting piece 15 are penetrated in the annealing furnace main body and wound iron cores 10 are passed through one of the conductors and are moved between tanks 1W4. partition plates 5W9 having recessed sections against the conductors 14 at the lower end and freely moving up and down are provided between each tank 1W4 and inactive gas preventing the oxidization of iron cores 10 is flowed to the tanks by fans 13 provided on the upper parts of the tanks 3 and 4 and gas temperature is adjusted by a latticed water cooling steel pipe 12. A current is simultaneously flowed to the conductors 14 for magnetic field adjustment.