Effects of Heat-Affected Zone Microstructure on Fracture Toughness of Two X70 Pipe Girth Welds

Park, Dong-Yeob; Amirkhiz, Babak Shalchi; Gravel, Jean-Philippe; Wang, Yiyu; Li, Leijun; Zavadil, Renata; Liang, Jie; Liu, Pei; He, A.; Arafin, Muhammad

doi:10.1007/s11661-017-4100-3

Cited by 5 publications

(3 citation statements)

References 31 publications

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“…The higher heat input in pipe A in comparison to pipe B caused grain coarsening in the weld of pipe A. It was shown that the toughness was significantly influenced by the microstructural constituents [13,14]. As illustrated in Figure 2c-f, for the columnar zone and coarse-grained equiaxed zone, pipe A had a lower fraction of acicular ferrite and a higher fraction of grain boundary ferrite (13.48%), and the ferrite grain size was coarser in comparison to pipe B.…”

Section: Effect Of the Heat Input And Microstructure On The Ctod Prop...mentioning

confidence: 99%

Crack-Tip Opening Displacement of Girth Welds in a Lean X70 Pipeline Steel

Li,

Yu,

Saini

et al. 2024

Materials

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Crack-tip opening displacement (CTOD) tests were conducted on girth welds of two API 5L X70 pipeline steels (pipe A and pipe B) to investigate the influence of base metal composition on the fracture toughness of the joint. CTOD measurements across the weld showed that the weld fusion zone had the lowest CTOD values for both pipes, with pipe B having a higher CTOD value than pipe A. Detailed microstructure characterization of the multi-pass weld showed that the fusion zone in both pipes consisted of three distinct zones: the columnar zone, the coarse equiaxed zone, and the fine equiaxed zone. Both the columnar zone and coarse-grained equiaxed zone had acicular ferrite and grain boundary ferrite microstructures, whereas the fine-grained equiaxed zone had a finer ferrite microstructure compared to the other two zones. The main difference between the two pipes was the variation in ferrite grain sizes and the volume fractions of grain boundary ferrite and acicular ferrite. In comparison to pipe B, pipe A, with a higher concentration of Mo, Ni, and Cu in both the base metal and the weld fusion zones, consisted of a higher volume fraction of grain boundary ferrite and a lower volume fraction of acicular ferrite in the columnar and coarse-grained equiaxed zones. The lower concentration of Mo, Ni, and Cu in pipe B likely resulted in the formation of a predominantly acicular ferrite microstructure in the fusion zone, thereby improving the toughness of the weld joint in comparison to pipe A.

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Section: Effect Of the Heat Input And Microstructure On The Ctod Prop...mentioning

confidence: 99%

Crack-Tip Opening Displacement of Girth Welds in a Lean X70 Pipeline Steel

Li,

Yu,

Saini

et al. 2024

Materials

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“…However, when the heat input increases to 40 kJ cm −1 , the austenite grain size tends to be stable. The increase of heat input causes the small particles pinned at the austenite grain boundary to dissolve, and the pinning effect cannot be achieved, also, the atomic diffusion velocity at the austenite grain boundary increases, which is beneficial to austenite grain growth [25][26][27][28].…”

Section: Cghaz Grain Size Analysismentioning

confidence: 99%

Effect of heat inputs on microstructure and mechanical properties in CGHAZ of BWELDY960Q steel

Qin¹,

Guo²,

Wang³

et al. 2021

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The Gleeble 1500 test machine was used to simulate the single-pass welding thermal cycle of BWELDY960Q steel under different heat input conditions. In this paper, microstructure observation and mechanical properties of BWELDY960Q steel specimens in coarse grain heat affected zone (CGHAZ) under different heat input conditions were investigated. The results show that under different heat input conditions, the microstructure of CGHAZ is lath martensite, granular bainite, or M-A constituent. As heat input increases, the number and size of the M-A constituent increase accordingly, and the microstructure gradually changes from lath martensite to granular bainite. Meanwhile, compared with the previous samples, the CGHAZ austenite grain diameter increases, and the grain size scale decreases. Furthermore, the value of the CGHAZ impact absorbing energy increases at first but then decreases, while microhardness monotonously decreases. At-20 • C compared with the base metal, the impact absorbing the energy of CGHAZ is significantly reduced, and embrittlement occurs. K e y w o r d s : BWELDY960Q steel, heat inputs, coarse grain heat affected zone, microstructure, mechanical properties

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“…A análise macrográfica realizada (Figura 13) permite verificar o efeito da soldagem multipasse e a inexistência de defeitos de soldagem, confirmando que o procedimento de soldagem executado foi adequado para evitar a ocorrência de trinca a frio. Neste aspecto, é importante ressaltar que o material em estudo (Tabela 2) apresenta elevada temperabilidade e, consequentemente, alta propensão para formação de martensita na ZTA, notadamente na região de grãos grosseiros, considerada a região crítica da ZTA [37][38][39][40][41][42][43], o que foi observado no presente trabalho (Figura 14).…”

Section: Propriedades Da Junta Soldadaunclassified

Avaliação de Juntas Soldadas de um Aço Fundido de Alta Resistência para a Indústria Offshore

et al. 2018

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Resumo Os torpedos de ancoragem são estruturas tubulares de aço carbono soldadas, e que tem sua ligação com as linhas de ancoragem que impedem o movimento das plataformas através de olhais de carregamento que são soldados nos tubos de construção. Como estes olhais apresentam geometria complexa, é importante a utilização de peças fundidas para a fabricação destes componentes, de forma a possibilitar o atendimento da demanda do mercado. Como a literatura técnica sobre este tipo de união soldada é ainda limitada, o presente trabalho estuda o comportamento de juntas soldadas de um aço fundido de alta resistência para utilização em olhais de torpedos de ancoragem de plataformas offshore. Para tanto, foram produzidas juntas soldadas com chanfro em K utilizando um aço de classificação ASTM A 148 Gr. 105-85 com resistência mecânica da ordem de 700 MPa, pelo processo eletrodo revestido, na posição plana, com preaquecimento de 200 °C e energia de soldagem média de 1,5 kJ/mm. Após a soldagem, foi realizado tratamento térmico pós-soldagem (TTPS) consistindo de aquecimento a 620 °C por 1 hora com resfriamento ao ar. As propriedades foram avaliadas por ensaios de tração, dureza, impacto Charpy-V e metalográficos por microscopia óptica e eletrônica de varredura com utilização da técnica de EBSD (eléctron backscatering difraction), tanto na condição de como soldado quanto após TTPS. Os resultados revelaram que, embora as propriedades mecânicas obtidas na junta soldada atendam os requisitos para a aplicação em todas as condições de análise, recomenda-se a execução do TTPS para alívio das tensões residuais e promover um revenimento da martensita de alta dureza do último passe de soldagem. Adicionalmente, verificou-se ser possível obter propriedades similares as de juntas soldadas de aços laminados usualmente utilizados em componentes de ancoragem.

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Effects of Heat-Affected Zone Microstructure on Fracture Toughness of Two X70 Pipe Girth Welds

Cited by 5 publications

References 31 publications

Crack-Tip Opening Displacement of Girth Welds in a Lean X70 Pipeline Steel

Crack-Tip Opening Displacement of Girth Welds in a Lean X70 Pipeline Steel

Effect of heat inputs on microstructure and mechanical properties in CGHAZ of BWELDY960Q steel

Avaliação de Juntas Soldadas de um Aço Fundido de Alta Resistência para a Indústria Offshore

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