| 摘要 |
PURPOSE:To remarkably shorten the time required to heat treat a tight coil when the coil is annealed, by perpendicularly placing the coil so that the through hole in the axial direction is turned sideways and by heating and cooling the coil. CONSTITUTION:A tight coil 21 is perpendicularly placed on a tray 11 so that the through hole 31 in the axial direction is turned sideways. When the perpendicularly placed coil 21 is heated in an atmospheric gas in an annealing furnace, the rate of heat transfer in the tight coil 21 in the axial directions (arrows B) is about 10-20 times the rate of heat transfer in the coil 21 in the diametral direction (arrow A). A part 21a most difficult to heat in the coil 21 undergoes heat transfer in the axial directions (arrows B) from right and left two directions and is heated in a short time. Thus, heat energy and atmospheric gas are saved and the thermal deformation of the tight coil is inhibited.
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