Creep Deformation Mechanism and Life Prediction of T91/S304H Welded Joint

The creep test of T91/Super304H joint is carried out at 610°C and 180–150 MPa. OM and SEM were used to characterize the microscopic changes before and after the joint creep, and the finite element simulation was carried out according to the actual operating parameters, which are used to analyze fail...

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Bibliographic Details
Published in:Strength of materials 2023-03, Vol.55 (2), p.340-354
Main Authors: Miao, K., Yin, Y. Y., Wang, T., Sun, G., Ma, J. J., Liu, J. F., Ji, D. M., Liu, C. H., Shen, L., Pan, W. G.
Format: Article
Language:English
Subjects:
Analysis
Characterization and Evaluation of Materials
Chemistry and Materials Science
Classical Mechanics
Coal-fired power plants
Cracking (fracturing)
Creep life
Creep strength
Creep tests
Deformation mechanisms
Ductile fracture
Ductile-brittle transition
Failure analysis
Filler metals
Finite element method
Fracture mechanics
Heat affected zone
Heat resistant steels
Heat treating
High temperature
Laves phase
Life prediction
Martensite
Martensitic stainless steels
Materials Science
Niobium
Service life
Solid Mechanics
Stress concentration
Welded joints
Welding
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Summary:The creep test of T91/Super304H joint is carried out at 610°C and 180–150 MPa. OM and SEM were used to characterize the microscopic changes before and after the joint creep, and the finite element simulation was carried out according to the actual operating parameters, which are used to analyze failure reason of the T91/S304H joint. Finally, the creep life prediction is carried out. The results show that the creep deformation of T91/S304H welded joints with nickel-based filler metal is controlled by the part of martensite T91. Meanwhile, the T91 heat-affected zone is the weak location of the joint. When the stress decreases, the creep life gradually increases, and the creep rupture changes from ductile fracture to brittle fracture. The distribution of Nb-containing phases improves the creep strength of S304H steel. In the process of high-temperature creep, stress concentration occurs between the coarser M 23 C 6 , the precipitated Laves phase and the matrix interface, which leads to the formation of creep holes and then gradually connected into cracks. The fracture mechanism is a typical type IV cracking model. The revised θ model can better predict the service life of T91/S304H welding.
ISSN:0039-2316
1573-9325
DOI:10.1007/s11223-023-00529-0