Disassembly of the thermal impact of coupling with a guaranteed stress state

Abstract

When repairing machines, inefficient technological operations are often used to disassemble fixed joints with a guaranteed stress state. The greatest difficulty is represented by such operations in the repair of large-sized units in diesel locomotive, carriage, ship repair and other enterprises.

Parts of assemblies and assembly units when disassembling using a press are subjected to plastic deformation, the mating surfaces are damaged, which makes it impossible to reuse them. For disassembly of such assembly units, it would be more appropriate to use heating the female parts.

When heated, the inner part expands and the tension present in the joint passes into the gap. After this, disassembly takes place without any difficulties and critical consequences for the disassembled parts.

At present, induction plants are widely used in industry for heating parts with high-frequency currents. With high-frequency heating, heat is released into the surface layer of the part, which leads to large temperature differences and internal stresses.

By reducing the frequency of the current by increasing the depth of penetration of the current into the metal, a deeper and more uniform heating of the female part is achieved. However, if the heating is not intensive enough, the heat generated in the inner part due to heat transfer goes into the surrounding part and free disassembly is impossible.

The article presents a method for determining the power and characteristics of induction-heating plants for disassembling large-sized couplings and experimental verification of their performance.

To study the electrical and thermal characteristics, induction heating systems were manufactured with industrial frequency currents for heating to disassemble a locomotive wheel pair.

As a result of the study, the possibility of using an induction-heating installations for dismantling large-sized equipment with industrial frequency currents was confirmed.