Avtomaticheskaya Svarka (Automatic Welding), #2, 2020, pp.24-28
Structural changes in the metal of welded joints of long-term operating steam pipelines
V.V. Dmytryk,. A.V. Glushko, S.P. Iglin
National Technical University «Kharkiv Polytechnic Institute», 2 Kirpichova Str., 61002, Kharkiv, Ukraine.
Increasing the service life of steam pipelines is a very urgent task for heat power engineering. The investigation of peculiarities of changing the metal structure in the areas of heat-affected-zone of welded joints of steam pipelines, which are operated for a long time in the conditions of creep, makes it possible to reduce the level of their damage and, consequently, increase the operating time. In the work the features of dislocations movement, dependence of creep rate on the structural state of welded joints are considered, and features of forming vacancies and creep pores are given. It was established that the formation of embryo pores in the conditions of creep depends on the degree of deformation of metal in welded joints, as well as on its structural state. 10 Ref., 7 Fig.
Keywords: structural changes, welded joints, operation, steam pipelines, dislocation, pores, damage, operating time
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