| 摘要 |
PURPOSE:To shorten the working time required to anneal a hollow metallic tube by forming a heat insulating layer around the tube and directly heating the tube from the inside so as to raise the temp. in a short time with reduced heat capacity. CONSTITUTION:This device for annealing a hollow metallic tube 12 is composed essentially of a holding frame 11 and cover plates 16. The frame 11 has a hollow part for holding the outside of the tube 12 in contact with the outside. The contact surface 13 has slender grooves 14 and the hollow part has been lined with a heat insulating layer 15. The cover plates 16 block up the tube 12 and the frame 11 from both sides. Gas feeding holes 17 leading to the interior of the tube 12 and holes 18 leading to the grooves 14 have been pierced in the cover plates 16. A heater 19 is fitted to the plates 16. The gap between the outside of the tube 12 and the inside of the frame 11 is evacuated or filled with an inert gaseous atmosphere, compressed gas is introduced into the tube 12 and the tube 12 is heated and held.
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