One of the key problems in the oil and gas industry is protecting pipelines from corrosion. As a result of many years of research, a number of solutions to this problem have been proposed. The article discusses the results of studies of the reliability and strength of a cone-flare connection made from pipes welded with high-frequency currents under the influence of loads simulating real operating conditions of the pipeline. The studies were carried out for two standard sizes of pipes made of steel grades 09GSF and 09G2S. To assess the stress-strain state (SSS) of the pipe end, which arises during the manufacture of the cone-flare joint, the process of deformation of the cone and flare parts, as well as the SSS of the connection itself, was simulated depending on the influence of external factors. Calculation and modeling were carried out using the ANSYS software package. It has been established that crimping the ends of pipes (making cones) and distributing them (making flares) does not create dangerous residual SSS. Modeling showed that deformation does not cause cracks or destruction of the pipe metal. The impact of operational loads on the cone-flare connection was simulated. Based on the calculations performed, it was concluded that the compounds under study are capable of ensuring reliable operation of the pipeline under loads equivalent to the normal operating conditions of conventional pipes. To confirm the results obtained, a set of bench tests was carried out. The last stage of a comprehensive assessment of the strength characteristics of the cone-flare connection was the study of samples after operation in field conditions. The connections were operated as part of an oil gathering pipeline at one of the fields in Western Siberia. The results obtained indicate the tightness and reliable protection of the ends of the pipes from the penetration of the transported medium into the connection of the type considered. It is concluded that the manufacturing technology of the cone-flare connection ensures the preservation of the viscoplastic properties of the pipe metal in the deformed zone. The internal protective coating at the cone-flare connection creates reliable protection against the development of corrosion processes, which guarantees trouble-free operation of the pipeline.
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