METHOD FOR PRODUCING Cr-CONTAINING NICKEL-BASED ALLOY TUBE

PROBLEM TO BE SOLVED: To inexpensively and uniformly form a chromium oxide film on the inside face of a Cr-containing nickel-based alloy tube. SOLUTION: The method for producing a Cr-containing nickel-based alloy tube includes: a step (1) (Fig. 1(a)) where an atmospheric gas composed of gaseous carbon dioxide is fed to the inside of a workpiece tube 1b before being charged to a continuous heat treatment furnace 5 from the tip side of the progressing direction thereof using a gas feed device 4b and gas introduction tubes 3 arranged so as to pierce the inside of the continuous heat treatment furnace 5; a step (2) (Fig. 1(b)) where the workpiece tube 1b is charged inside the continuous heat treatment furnace 5 as an atmospheric gas composed of gaseous carbon dioxide is fed to the inside thereof; and a step (3) (Fig. 1(c)) where, after the tip of the workpiece tube 1b reaches the outlet side of a heating zone 5a in the continuous heat treatment furnace 5, the feeding of the atmospheric gas composed of gaseous carbon dioxide to the inside of the workpiece tube 1b is switched to the feeding from the other gas feed device 4a. COPYRIGHT: (C)2007,JPO&INPIT