The Paton Welding Journal, 2023, №06



2023 №06 (04)

DOI of Article 10.37434/tpwj2023.06.05

2023 №06 (06)

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The Paton Welding Journal, 2023, #6, 32-40 pages

Mathematical modeling of residual stress relaxation during performance of postweld heat treatment

O.V. Makhnenko, O.S. Milenin, O.F. Muzhychenko, S.M. Kandala, O.M. Savytska, G.Yu. Saprykina

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

Abstract
In order to lower the level of residual stresses, welded joints of a number of structural steels are subjected to general or local postweld heat treatment by the high-temperature tempering mode. Mathematical modeling methods are widely used, alongside the experimental investigation methods, to satisfy the continuously growing requirements to welded joint quality and to optimize the welding technology. Mathematical modeling of the process of welded joint heat treatment is often performed using a simplified creep function by Norton-Bailey law at a fixed soaking temperature, but here the processes of ductile deformation taking place during slow prolonged heating and cooling, are ignored. The effectiveness of application of different models of temperature creep for mathematical modeling of the processes of relaxation of residual stresses in welded joints was studied in this work with the purpose of developing recommendations for their application for various characteristic cases of postweld heat treatment. Comparison of the results of modeling the process of stress relaxation performed on a number of examples, showed that the simplified creep function at short-term soaking during general furnace treatment can give an error compared to a more general creep model. Modeling of the local heat treatment technology revealed that the complex geometry of the component and poor choice of the heating element arrangement may lead to negative consequences, namely formation of new high residual stresses. Proper modeling of the processes of relaxation and redistribution of residual stresses in welded joints and structures as a result of general (furnace) or local post-weld heat treatment may optimize the process of furnace heat treatment and improve the quality and fatigue life of the welded structures. 16 Ref., 1 Tabl., 12 Fig.
Keywords: postweld heat treatment, high-temperature annealing, residual welding stresses, stress relaxation, mathematical modeling, creep function

Received: 10.05.2023
Accepted: 17.07.2023

References

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