Application with Simultaneous Electrocontact Heating Stretching to Reduce Residual Stresses in the Heat Exchange Tube

The main reason of appearance and growth of corrosion damages of the nuclear steam generator heat exchanger tubes is the process of stress-corrosion cracking of metal under the influence of residual tensile stress.The article contain the suggestion of the method that combines the operation of heat processing and straightening of pipes by stretching. The approbation of the method was carried out in the laboratory conditions. There is described the construction and working principle of a trial installation. During the experiments different parameters of electrocontact heating with stretching were tested. Approbation showed that the proposed method can reduce the level of tensile residual stresses or get compressive residual stresses in the wall of the tubes, which increases their resistance to corrosion.Keywords:Steam generator, heat exchange tubes, stress corrosion cracking, intercrystalline corrosion, residual stresses