Heavy-Section 2[fraction one-quarter]Cr-1Mo Steel for Hydrogenation Reactors

Murakami, Yoshikuni; Nomura, Tohru; Watanabe, Jurō

doi:10.1520/stp28425s

Cited by 10 publications

(3 citation statements)

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“…A significant part of the hydrogen absorbed by the WM during welding and operation on the steam piping or on the hydrogenation reactor could migrate to the zones of the volumetric stress state and, thereby, affect the mechanical properties of the WM during tensile testing of specimens [52,53]. After all, it is known that hydrogen can contribute both to the strengthening of metals (at the macro level) [54] and their plastification (at the micro level) [55].…”

Section: The Properties Of Wm After Degassing In Vacuummentioning

confidence: 99%

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: The Properties Of Wm After Degassing In Vacuummentioning

confidence: 99%

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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show abstract

“…In the 1970s, Bruscato [2] introduced a brittleness factor, Materials 2024, 17, 205 2 of 12 X = (10P + 5Sb + 4Sn + As) × 102, which can be used to predict the brittleness sensitivity of metals. Watanabe [3], in conjunction with experiments on plates and forgings, identified a brittleness sensitivity factor, J = (Si + Mn)(P + Sn) × 104. As X and J values increase, steel transitions towards embrittlement.…”

Section: Introductionmentioning

confidence: 99%

Regulation Law of Tempering Cooling Rate on Toughness of Medium-Carbon Medium-Alloy Steel

Yang,

Xu,

Zhao

et al. 2023

Materials

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Temper embrittlement is a major challenge encountered during the heat treatment of high-performance steels for large forgings. This study investigates the microstructural evolution and mechanical properties of Cr-Ni-Mo-V thick-walled steel, designed for large forgings with a tensile strength of 1500 MPa, under different tempering cooling rates. Optical microscopy (OM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) were employed to analyze the microstructural features. The results demonstrate that the embrittlement occurring during air cooling after tempering is attributed to the concentration of impurities near Fe3C at the grain boundaries. The low-temperature impact toughness at −40 °C after water quenching reaches 29 J due to the accelerated cooling rate during tempering, which slows down the diffusion of impurity elements towards the grain boundaries, resulting in a reduced concentration and dislocation density and an increased stability of the grain boundaries, thereby enhancing toughness. The bainite content decreases and the interface between martensite and bainite undergoes changes after water quenching during tempering. These alterations influence the crack propagation direction within the two-phase microstructure, further modifying the toughness. These findings contribute to the understanding of temper embrittlement and provide valuable guidance for optimizing heat treatment processes to enhance the performance of high-performance steels in large forgings.

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“…In the 1970s, Bruscato [2] introduced a brittleness factor X = (10P + 5Sb + 4Sn + As) × 102, which can be used to predict the brittleness 2 sensitivity of metals. Watanabe [3], in conjunction with experiments on plates and forgings, identified a brittleness sensitivity factor J = (Si + Mn)(P + Sn) × 104. As X and J values increase, steel transitions towards embrittlement.…”

Section: Introductionmentioning

confidence: 99%

Regulation Law of Tempering Cooling Rate on Toughness of Medium Carbon Medium

Yang,

Xu,

Zhao

et al. 2023

Preprint

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Temper embrittlement is a major challenge encountered during the heat treatment of high-performance steels for large forgings. This study investigates the microstructural evolution and mechanical properties of Cr-Ni-Mo-V thick-walled steel, designed for new large forgings with a tensile strength of 1500 MPa, under different tempering cooling rates. Optical microscopy (OM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) were employed to analyze the microstructural features. The results demonstrate that the embrittlement occurring during air cooling after tempering is attributed to the concentration of impurities near Fe3C at the grain boundaries. The low-temperature impact toughness at -40°C after water quenching reaches 29 J due to the accelerated cooling rate during tempering, which slows down the diffusion of impurity elements towards the grain boundaries, resulting in reduced concentration and dislocation density, and increased stability of the grain boundaries, thereby enhancing toughness. the bainite content decreases and the interface between martensite and bainite undergoes changes after water quenching during tempering. These alterations influence the crack propagation direction within the two-phase microstructure, further modifying the toughness. These findings contribute to the understanding of temper embrittlement and provide valuable guidance for optimizing heat treatment processes to enhance the performance of high-performance steels in large forgings.

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Heavy-Section 2[fraction one-quarter]Cr-1Mo Steel for Hydrogenation Reactors

Cited by 10 publications

References 0 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

Regulation Law of Tempering Cooling Rate on Toughness of Medium-Carbon Medium-Alloy Steel

Regulation Law of Tempering Cooling Rate on Toughness of Medium Carbon Medium

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