TPWJ, 2015, #1, 18-23 pages
EVALUATION OF OPERABILITY OF THE MAIN PIPELINE WITH LOCAL WALL THINNING AT REPAIR BY ARC SURFACING
Journal The Paton Welding Journal
Publisher International Association «Welding»
ISSN 0957-798X (print)
Issue № 1, 2015 (January)
E.A. Velikoivanenko, G.F. Rozynka, A.S. Milenin And N.I. Pivtorak
E.O. Paton Electric Welding Institute, NASU. 11 Bozhenko Str., 03680, Kiev, Ukraine. E-mail: firstname.lastname@example.org
Welding surfacing is one of the most rational methods of repairing the main pipelines without taking them out of service, particularly in the case of the need to eliminate typical defects of local metal loss through corrosion. Here welding application on a pipeline, which is at high internal pressure, envisages a thorough optimization of technological parameters of this process in terms of safety and effectiveness of repair-and-renewal operations, in particular, on the base of the results of modeling the occurring physico-mechanical processes kinetics. In this study a package of tools was developed for mathematical modeling of the process of multipass welding surfacing of thinning defects of the main pipeline elements to predict their technological strength and post-repair residual life. For this purpose an integrated approach of numerical analysis of the kinetics of temperatures, stress-strain state and processes of tough fracture of pipeline material has been implemented. A numerical criterion has been proposed, which allows, with a slight conservatism, prediction of formation of structure state, close to the limiting one, as well as guaranteeing the required load-carrying capacity of the pipeline, after repair of the detected defect of discontinuity type. The case of multipass surfacing repair of an inadmissible defect of the main pipeline wall thinning was used to study the characteristic peculiarities of the influence of the main technological parameters on the structure technological strength and its residual life. 17 Ref., 1 Table, 6 Figures.
arc surfacing, main pipeline, defect, local wall thinning, repair under pressure, safety of repair-and-renewal operations, plastic instability, tough fracture
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