| 2025 №04 (05) | 2025 №04 (07) |
"Avtomatychne Zvaryuvannya" (Automatic Welding), #4, 2024, pp. 40-46
Influence of the structural phase state on the properties of welded joints of steam pipelines
V.V. Dmitrik, Chen Xinlei
National Technical University «Kharkiv Polytechnic Institute». 2 Kyrpychova Str., 61002, Kharkiv, Ukraine. E-mail: dmitrikvitali@gmail.comThe paper considers the peculiarities of the influence of the structural-phase state on the properties of welded joints of steam pipelines, as well as on their reliability and residual service life. The determination of physical and mechanical properties, reliability, and service life is mostly related to welded joints of those steam lines whose operating parameters are as follows: temperature of 545 °C, steam pressure of 25.5 MPa. It was found that with an increase in the operating time of welded joints, gradual transformation of the ferritic-bainitic structure into a ferritic-carbide mixture occurs in their structure, the amount of which increases accordingly. The presence of such a mixture ensures a decrease in the mechanical properties of the metal of welded joints and contributes to its damage by the brittle mechanism. The growth rate of the ferritic-carbide mixture largely depends on the initial structure of the welded joints. It was found that the presence of pearlite in the initial structure accelerates the formation of a ferritic-carbide mixture. 10 Ref., 1 Tabl., 12 Fig.
Keywords: structural-phase state, heat-resistant steels, reliability, service life, damageability, welded joints, sections of the heat-affected zone, ferritic-carbide mixture, mechanical properties
Received: 21.04.2024
Received in revised form: 30.06.2025
Accepted: 05.07.2025
References
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