JPS57181723A - Slip preventing method in case when annealed coil is rewound - Google Patents

Abstract

PURPOSE:To prevent looseness of winding, to generate no scratch at all, and to elevate yield, by inserting a heat insulating ring into a coil center hole and suppressing a drop of temperature of the inside diameter part, when cooling a coil in an annealing process. CONSTITUTION:A coil 1 is placed on a bottom spacer 7, and an inside circumferential heat insulating ring 8 is inserted into a center hole. Subsequently, the coil into which the inside circumferential heat insulating ring 8 has been inserted is piled up in order through a top spacer 9. After that, when cooling air is blown through a duct 10, cooling advances mainly from the outside circumferential part of the coil 1, a temperature becomes lower as it gets near the outside circumferetial part, but in the inside diameter part from the radius of the coldest point in the coil, cooling from the inside circumferential part is obstructed owing to the inside circumferential heat insulating ring 8, and a temperature drop does not advance to the extent of the outside diameter part. Accordingly, a temperature distribution in a section of the coil becomes like a curve (c), a temperature drop of the coil inside diameter part is suppressed, surface pressure between strips based on thermal stress is maintained enough in the coil inside diameter part, and no loose state is generated.