Automatic Welding, 2022, №11



2022 №11 (01)

DOI of Article 10.37434/as2022.11.02

2022 №11 (03)

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Avtomaticheskaya Svarka (Automatic Welding), #11, 2022, pp. 12-17

Recovery and recrystallization of metal of steam line welded joints during long-term service

V.V. Dmytryk, I.V. Kasyanenko, Yu.M. Latynin

NTU «Kharkiv Polytechnic Institute». 2 Kyrpychova Str., 61002, Kharkiv, Ukraine. E-mail: igorkasyanen@gmail.com

The processes of recovery and recrystallization occur in the metal of welded joints of heat-resistant pearlitic steels at their long-term operation. The running of these processes is very different from similar processes taking place at normal annealing. At recrystallization proceeding in the welded joint metal, some intergranular boundaries disappear, and the formed grains take an elongated shape. A decrease of strength by approximately 10…15 and of impact toughness by 15…18 % is observed in the recrystallized metal. It is found that recovery and recrystallization as components of the overall process of transformation of the initial structure of welded joint metal into a ferrite-carbide mixture proceed at its plastic deformation. The distribution of vacancies changes during recrystallization, differing essentially in the HAZ subzones. The highest deformation level is observed in the incomplete recrystallization subzone of the HAZ. Studying the features of recovery and recrystallization processes is relevant for determination of the reliability of operation and life of welded joints, as well as development of new heat-resistant steels, which will operate at higher working parameters – temperature and time. 11 Ref., 13 Fig.
Keywords: welded joints, heat-resistant steels, recovery, recrystallization, life, creep conditions, structural phase state, mechanical propertiesі


Received: 24.06.2022

References

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