CONTINUOUS HEAT TREATMENT FURNACE AND UTILIZING THE SAME, METAL TUBE AND HEAT TREATMENT METHOD

摘要

One aspect of the present invention provides a continuous heat treatment furnace in which an atmosphere-control gas is introduced to a heating chamber 1 having a heating zone 1 a, metal tubes are continuously charged along an axial direction from a furnace entrance 2 a, and the metal tube subjected to a heat treatment is taken out from a furnace exit 2 b. The continuous heat treatment furnace includes a front chamber 4 which has a preheating zone 3 on an entrance side of the heating chamber and seal curtains 5 a and 5 b which are located on an entrance side and an exit side of the front chamber. Another aspect of the present invention provides a metal tube subjected to the heat treatment using the continuous heat treatment furnace, and yet another aspect of the present invention provides a heat treatment method for performing the heat treatment using the heat treatment furnace. Desirably a rear chamber 6 is provided on an exit side of the heating chamber and seal curtains 7 a are attached onto an entrance side of the rear chamber. Even if a post-cold working washing process is performed only by alkali degreasing and washing, an adhered substance to inner and outer surfaces of the metal tube can easily be removed before the heat treatment by the heat treatment furnace and the heat treatment method.