| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of controlling the flowing-amount of atmospheric gas, with which the stuck material on the surface of a tube can be easily removed after cold-working and the reduction of the cost can be achieved without lowering efficiency of heat-treatment. SOLUTION: In a method of operating a continuous heat-treatment furnace, the atmospheric gas is introduced in the furnace, the tube is charged along the axial direction from the inlet of the furnace, and the tube subjected to the heat-treatment is carried out from the outlet of the furnace. In the method of controlling the flowing amount of the atmospheric gas in the continuous heat-treatment furnace where sealing curtains suspended at the inlet and the outlet of the furnace so as to cover the entire surface, are provided, and the atmospheric gas is charged under the condition that when the entire length from the top end to the rear end of the pipe to be charged passes through the sealing curtains provided to the inlet side of the furnace, gas flowing velocity V flowing in the tube obtained from (1) formula: V=ΔP×r<SP>2</SP>/(8×μ×L) becomes higher than tube feeding velocity U. There are also provided the continuous heat-treatment furnace using the method of controlling the flowing amount of the atmospheric gas, and the heat-treated pipe. COPYRIGHT: (C)2010,JPO&INPIT
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