| 摘要 |
PURPOSE:To improve the efficiency of respective treatments for ferrous laminated layers and to economize on energy by disposing successively, via shielding mechanisms, a deoiling furnace, annealing furnace and bluing furnace to a transfer path for materials to be treated and supplying an inert gas to respective furnaces from the outside. CONSTITUTION:The inert gas is fed from a supply device 22 into the deoiling furnace 2 when the ferrous products such as laminated cores advance into the furnace. The products are at the same time heated by a heater by which the oil-component sticking to the surface thereof is evaporated. The materials to be treated are then transferred into the annealing furnace 3 by passing through a communication cylinder which has the atmosphere shielding mechanism 23a and into which the inert gas is blown. The inert gas is fed into the furnace 3 and the materials to be treated are annealed by the heating with the heater during the transfer, by which an Fe3O4 film is formed thereon. The materials enter thereafter a communicating cylinder having the atmosphere shielding mechanism 23b where the materials are cleaned by a barrier gas, then the materials enter the bluing furnace 4. The dry inert gas contg oxygen at a high concn. is fed through an adding part 46 of a branch pipeline 45 into the furnace 4 where the materials are subjected to the bluing treatment while the materials are slowly cooled. The formation of the oxide film is thus intensified.
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