Effect of Electrocontact Heating with Simultaneous Tension on the Residual Stresses in Stainless-Steel Pipes

The main reason for the formation and growth of corrosion-related defects in the heat-exchange pipes of steam generators at nuclear power plants is stress corrosion cracking of the metal under the influence of residual tensile stresses. A method is proposed for alleviating this problem by simultaneously subjecting the pipes to heat treatment and straightening while undergoing tension. The method has been proven reliable in laboratory tests. The design and principle of operation of an experimental unit for use of the method are also described. Different parameters characterizing electrocontact heating with tension were used in the experiments that were performed. The testing showed that the proposed method can either reduce the residual tensile stresses in the pipes or create residual compressive stresses in their wall, which improves the pipes’ resistance to corrosion.