Weld Repair Technique for Petroleum Product Pipeline in Extreme Conditions of Prolonged Thermal Cycling

Abstract

The paper presents the results of experimental research on the development of a repair technique for a pipeline transporting hydrogen mixed with petroleum vapors, which has been in operation for 25 years at Mozyr Oil Refinery, the largest oil enterprise of the Republic of Belarus. The failure of this pipeline was caused by a crack formed in the weld root and its propagation along the fusion line of the heterogeneous weld joint. The developed technique made it possible to prevent further crack propagation without interrupting the refinery fractionation column operation. Welding of the main weld should be performed on a previously deposited damping layer. The damping layer must be deposited by using welding materials, the welding method and the technique that lead to creating a nonoriented dendritic structure. For this purpose, a welding material that has an energy of crack initiation and propagation greater than the energy of crack propagation in the base metal must be used. The composition of the weld must include chemical elements that inhibit the intensity of diffusion processes and increase the strength of the interatomic forces of the austenitic matrix at the pipeline operating temperature.