Indirect heating furnace for the surface treatment of a metal or the like employing a salt bath.

摘要

An indirect heating furnace for the surface treatment of a metal or the like, employing a salt bath, comprises a furnace body (1), provided with a concave portion (11) containing a thermal medium (2) mainly composed of a chloride, and a heat-resistant vessel (3) placed in the concave portion, which contains a treatment material (4) mainly composed of a borate, and at least one pair of electrodes (12) embedded in the side wall of the concave portion (11) adjacent to the bottom portion thereof. The electrodes heat the thermal medium which in its turn heats the surface treatment material. The temperature of the surface treatment material is easily raised within a short period of time so as to extend the actual useful life of the treatment material even at a temperature as high as about 1,200 DEG C.