Automatic Welding, 2025, №05

2025 №05 (01)

DOI of Article 10.37434/as2025.05.02

2025 №05 (03)

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"Avtomatychne Zvaryuvannya" (Automatic Welding), #5, 2024, pp. 16-24

Residual stresses in the joint of the collector to the DN1200 branch pipe of the PGV-1000 steam generator due to local heat treatment

O.V. Makhnenko, O.F. Muzhichenko, I.I. Prudkiy, N.R. Basistyk

E.O. Paton Electric Welding Institute of the NAS of Ukraine 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: makhnenko@paton.kiev.ua

When assessing the extension of the service life of WWER-1000 NPP power units, the welded joint of the collector to the DN1200 branch pipe of the PGV-1000 steam generator is an object of increased attention due to its tendency to the formation of discontinuity defects. In order to obtain more detailed information regarding the loading of this welded joint, mathematical modeling of the kinetics of formation of residual stresses and plastic strains, as a result of local postweld heat treatment in the high-temperature tempering mode, was carried out using the finite element method. The complex geometry of the joint and the local arrangement of the heaters cause significant nonuniformity of heating during heat treatment, which can lead to negative consequences, namely, formation of high residual tensile stresses in the hazardous zones of the welded joint. It is proven that the axisymmetric 2D finite element model of the joint with the shortest length of the DN1200 branch pipe provides sufficient conservativeness of the results compared to the general 3D model. 18 Ref., 1 Tabl., 11 Fig.
Keywords: PGV-1000 steam generator, welded joint No. 111, local heat treatment, residual stresses, plastic strains, mathematical modeling, creep


Received: 27.02.2025
Received in revised form: 21.03.2025
Accepted: 15.09.2025

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