CONTINUOUS HEAT TREATMENT METHOD FOR METAL PIPES

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 1a, metal tubes are continuously charged along an axial direction from a furnace entrance 2a, and the metal tube subjected to a heat treatment is taken out from a furnace exit 2b. 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 5a and 5b 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 7a 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.