Degradation of Welded Joints of Steam Pipelines of Thermal Electric Power Plants in Hydrogenating Media

Nykyforchyn, H. М.; Student, О. Z.; Dzioba, Ihor; Stepanyuk, S.M.; Markov, A. D.; Onyshchak, Ya. D.

doi:10.1007/s11003-005-0122-x

Cited by 12 publications

(6 citation statements)

References 2 publications

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“…The hardness of WM in the initial state (the specimen was cut from the model WJ) exceeded the hardness of BM (steel 15Kh1M1F) almost throughout the entire thickness of the pipe wall, which is in accordance with data in [45]. In the deeper layers of the pipe wall, the hardness of WM in the initial state gradually decreased to 180 .…”

Section: Sensitivity Of Hardness To Weld Joint Degradationsupporting

confidence: 86%

“…Moreover, they were quite sensitive to changes in the state of the WM as a result of long-term operations. This is despite the previously noted low sensitivity of hardness, strength, and plasticity in tension to the degradation of BM [45]. A noticeable decrease in the tensile strength (26%) of the WM during operation indicates a decrease in its cohesive strength and tear resistance (Figure 2a).…”

Section: Changes In Strength Ductility and Toughness Characteristics ...mentioning

confidence: 73%

“…plasticity in tension to the degradation of BM [45]. A noticeable decrease in the tensile strength (26%) of the WM during operation indicates a decrease in its cohesive strength and tear resistance (Figure 2a).…”

Section: Changes In Strength Ductility and Toughness Characteristics ...mentioning

confidence: 99%

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Analysis of Mechanical Properties of Welded Joint Metal from TPP Steam Piping after Its Operational Degradation and Hydrogenation

Hutsaylyuk,

Student,

Maruschak

et al. 2023

Materials

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In this paper, the mechanical properties of various zones of the welded joints of a heat-resistant steel 15Kh1M1F in different states (in the initial state, after an operation on the main steam piping of a thermal power plant (TPP) for 23 years) were determined, and the fracture surfaces were analyzed using scanning electron microscopy (SEM) images. The effect of hydrogen electrolytic charging on mechanical behavior and fracture mechanism was also studied. The long-term operation of welds resulted in a higher degradation degree of the weld metal compared to the base one, indicated by the deterioration of mechanical properties: decrease in hardness, strength characteristics, and reduction in area, which was accompanied by an atypical increase in elongation at fracture. All studied zones of the operated welded joints were characterized by higher hydrogen content, 2.5–3 times higher than that in the initial state. Additional hydrogen charging of the weld joint metal led to a decrease in the strength and ductility characteristics, more significantly for the operated weld compared with the non-operated one. This justified the possibility of using short-term tests of hydrogenated WM in the air to assess the degree of its damage during operation on a steam piping.

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Section: Sensitivity Of Hardness To Weld Joint Degradationsupporting

confidence: 86%

Section: Changes In Strength Ductility and Toughness Characteristics ...mentioning

confidence: 73%

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Analysis of Mechanical Properties of Welded Joint Metal from TPP Steam Piping after Its Operational Degradation and Hydrogenation

Hutsaylyuk,

Student,

Maruschak

et al. 2023

Materials

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“…Modern technologies of production and inspection do not allow the presence of crack-type defects in newly manufactured components. However, during long-term operation in conditions of cyclic loads and environmental impact, cracks in the elements may arise and develop from microstructural defects (e.g., from particles of large inclusions) [1,2]. A particularly high risk of initiation and development of cracks in a component is found when inclusions are grouped in one plane, which leads to the development of internal delamination cracks [3,4,5,6].…”

Section: Introductionmentioning

confidence: 99%

Fracture Mechanisms of S355 Steel—Experimental Research, FEM Simulation and SEM Observation

Dzioba

Lipiec

2019

Materials

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In this study, the fracture mechanisms of S355 ferritic steel were analyzed. In order to obtain different mechanisms of fracture (completely brittle, mixed brittle and ductile or completely ductile), tests were carried out over a temperature range of −120 to +20 °C. Our experimental research was supplemented with scanning electron microscopy (SEM) observations of the specimens’ fracture surfaces. Modeling and load simulations of specimens were performed using the finite element method (FEM) in the ABAQUS program, and accurate calibration of the true stress–strain material dependence was made. In addition, the development of mechanical fields before the crack tip of the cracking process in the steel was analyzed. The distributions of stresses and strains in the local area before the crack front were determined for specimens fractured according to different mechanisms. Finally, the conditions and characteristic values of stresses and strains which caused different mechanisms of fracture—fully brittle, mixed brittle and ductile or fully ductile—were determined.

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“…At the same time, the studies on the condition of structural steels for the critical-purpose objects in long-term service (in particular, power engineering [7][8][9][10][11], aviation [12], chemical [13], gas and oil industries, and transportation systems of marketing hydrocarbons [14][15][16][17][18]) pointed to the significant degradation of metal properties due to the effect of different operating factors. Correspondingly, this problem can also concern the steels of the Shukhov towers.…”

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confidence: 99%

Analysis of Long-Term in-Service Degradation of the Shukhov Tower Elements

et al. 2015

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The condition of old and repair steels of the Shukhov tower elements that were in service for~110 and 70 years, respectively, was analyzed. They were assessed with several mechanical characteristics: hardness, static and impact strength, and plasticity. Both steels are shown to exhibit extra low hardness and brittle fracture resistance, which cannot be explained only by the quality of rolled metal of that time, with lower mechanical characteristics of old steel. It was assumed that in-service degradation of steel properties took place due to the evolution of scattered damage. Larger elongation of old steel at lower hardness and impact strength also points to this fact. It was also found that strength and plasticity of both steels, determined in the medium of synthetic acid rain, were lower than in air. The presence of in-service damages in the bulk of the metal was confirmed fractographically, in the case of possible hydrogen absorption by the specimens from the medium, they initiate brittle fracture in the central part of their cross-section.

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Degradation of Welded Joints of Steam Pipelines of Thermal Electric Power Plants in Hydrogenating Media

Cited by 12 publications

References 2 publications

Analysis of Mechanical Properties of Welded Joint Metal from TPP Steam Piping after Its Operational Degradation and Hydrogenation

Analysis of Mechanical Properties of Welded Joint Metal from TPP Steam Piping after Its Operational Degradation and Hydrogenation

Fracture Mechanisms of S355 Steel—Experimental Research, FEM Simulation and SEM Observation

Analysis of Long-Term in-Service Degradation of the Shukhov Tower Elements

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