Avaliação da Influência de Tratamentos Térmicos Pós-Soldagem Sobre a Microestrutura e Propriedades Mecânicas de Juntas de um Aço API 5L X70Q

Araújo, Lívia Carla Silva de; Cândido, Luiz Cláudio; Trindade, Vicente Braz; Porcaro, Rodrigo Rangel

doi:10.1590/0104-9224/si2002.05

Cited by 5 publications

(10 citation statements)

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“…There is a huge advantage in the manufacturing process of seamless steel pipes, because from a relatively simple steel, as the steel in this research, and with the assistance of conventional heat treatment processes, it is possible to achieve intermediate grades, unlike welded pipes that require more elaborate and rigorous chemical composition in addition to a specific thermomechanical processing with many processing parameters such as reheating temperature, percentage reduction, deformation temperature, cooling rate, and coiling temperature. Unfortunately, much of what is studied about seamless steels is not published due to industrial restrictions and information security, but engineers and researchers in the Vallourec Group (one of the most important world producer of seamless steel pipes) has access to this information and mention the advantages of this route for the production of pipes in their papers [32][33][34] . Therefore, the present research was carried out to evaluate the behavior of an API 5L PSL2 seamless pipeline steel manufactured by one of the Vallourec steel plants in Brazil.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Microstructure and Mechanical Properties of Seamless Steel Pipes API 5L Type Obtained by Different Processes of Heat Treatments

2017

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This research presents the influence of manufacturing processes and heat treatments on the resulting microstructures and mechanical properties of an API 5L PSL2 seamless steel pipe. Three different conditions are considered -as rolled, normalized and quenched and tempered -to obtain the grades X42R, X42N and X70Q, respectively. Scanning electron microscopy techniques was used to characterize the resultant microstructures. Tensile, hardness, impact, fracture toughness (J integral) and fatigue crack growth tests (da/dN x ΔK) were used to study the materials mechanical behavior. The results show the possibility of achieving API grades for a seamless pipeline steel, through suitable heat treatments. The microstructural modifications and mechanical properties changes observed showed a remarkable structure-properties relationship of the steel, and attempt to a proper selection as required by the structural design. The quenching and tempering process increased tensile mechanical properties and fracture toughness, but combined to a significant decrease in fatigue crack growth resistance.

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Section: Introductionmentioning

confidence: 99%

Evaluation of Microstructure and Mechanical Properties of Seamless Steel Pipes API 5L Type Obtained by Different Processes of Heat Treatments

2017

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“…Em microscópio eletrônico de varredura foram avaliados qualitativamente os agregados ferrita carboneto e constituintes martensita-austenita retida (M-A), após ataque com reagente Le Pera (solução de 1g de metabissulfito de sódio em 10mL de água destilada misturado a igual proporção de solução de 4g de ácido pícrico em 100mL de etanol) [12].…”

Section: Materiais E Métodosunclassified

“…Observa-se na Figura 5 uma microestrutura refinada e homogênea formada por martensita revenida e bainita, típico para este aço [1,12], em (b) destaca-se a bainita identificada em microscopia eletrônica de varredura. Nas micrografias da Figura 6 observam-se constituintes típicos de zona fundida para aços baixo carbono.…”

Section: Caracterização Microestruturalunclassified

“…De acordo com Araújo et al [12] e Trindade et al [8], após o ataque Le Pera a identificação do M-A pode ser feita utilizando-se MEV. Observa-se na Figura 7b a presença predominante de agregados M-A e na Figura 7a destacam-se várias regiões de ferrita-carboneto com poucas regiões de M-A.…”

Section: Junta 1/2v Fa (%) Fp(g) (%) Fp (I) (%) Fs (A) (%) Fs (Na) (%unclassified

“…Observa-se na Figura 7b a presença predominante de agregados M-A e na Figura 7a destacam-se várias regiões de ferrita-carboneto com poucas regiões de M-A. Os critérios de classificação dos constituintes M-A foram os mesmos adotados em [12], ou seja, as regiões atacadas correspondem à ferrita e as regiões ricas em carbono não são atacadas, sendo possível identificar os agregados Ferrita Carbonetos com morfologia descontínua e o agregado M-A massivo como indicado na Figura 7 . Essas imagens corroboram que no chanfro ½ V houve maior formação de M-A, uma vez que este constituinte se forma em maiores taxas de resfriamento, por um mecanismo que torna estável a austenita remanescente devido ao enriquecimento de carbono rejeitado no crescimento da ferrita [15,17].…”

Section: Junta 1/2v Fa (%) Fp(g) (%) Fp (I) (%) Fs (A) (%) Fs (Na) (%unclassified

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Características Microestruturais e Mecânicas ao Longo da Seção Transversal de Juntas Soldadas em Multipasses pelo Processo GMAW de um Aço API 5L X65Q

et al. 2017

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Este é um artigo publicado em acesso aberto (Open Access) sob a licença Creative Commons Attribution Non-Commercial, que permite uso, distribuição e reprodução em qualquer meio, sem restrições desde que sem fins comerciais e que o trabalho original seja corretamente citado.Recebido: 09 Abr., 2017 Aceito: 08 Ago., 2017 E-mail: vicentebraz@yahoo.com.br (VBT) Resumo: Características microestruturais e mecânicas foram avaliadas ao longo da seção transversal de juntas obtidas por soldagem (GMAW), de tubos sem costura de aço API 5L X65Q. Dois tipos de juntas foram obtidas a partir da confecção de chanfro V e ½ V. Dividindo-se as chapas soldadas em 8 camadas espaçadas de 3mm, no sentido transversal, corpos de prova foram confeccionados para ensaios de tração, microdureza Vickers e análise química. Foi realizada ainda caracterização metalográfica no metal base e nas juntas soldadas. Observou-se pequena alteração na composição química do metal de solda entre as camadas da junta V e junta ½ V. A maior taxa de resfriamento promoveu maior fração de ferrita acicular no chanfro ½ V. Alguns corpos de prova de tamanho reduzido não atenderam aos limites mínimos de escoamento e de resistência especificados na Norma API 5L, resultado atribuído à presença de descontinuidades em algumas regiões da solda. A maior microdureza Vickers da junta ½ V foi atribuída à maior presença de ferrita acicular. A adoção de chanfro estreito para aumento de produtividade na soldagem do aço em estudo não impactou negativamente as propriedades da junta, entretanto, aumentou a ocorrência de falta de fusão na face do bisel. Palavras-chave:Tubos sem costura; Aços API 5L X65Q; GMAW; Chanfro ½ V. Microstructural and Mechanical Characterization Across the Cross Section of Multipass GMAW Weld Joints of an API5L X65QAbstract: Microstructural and mechanical characteristics were evaluated along the cross section of joints obtained by (GMAW) of seamless API 5L X65Q steel pipes. Two types of joints were obtained from the bevel V and ½ V. By the division of the welded plates into 8 layers spaced 3 mm in the transverse direction, specimens were prepared for tensile tests, Vickers microhardness and chemical analysis. In addition, metallographic characterization was performed on the base metal samples and welded joints. It was observed a small change in the chemical composition of the weld metal between the 1st and 8th layer of the V joint and ½ V joint. The higher cooling rate of the ½ V bevel promoted higher acicular ferrite content. Some specimens of reduced size did not meet the minimum tensile properties limits specified in API 5L, a result attributed to the presence of discontinuities in some regions of the weld. The highest Vickers microhardness of the ½ V joint was attributed to the greater presence of the acicular ferrite. The adoption of narrow groove to improve the welding productivity did not negatively impact the properties of the joint, however, increased the occurrence of lack of fusion in the bevel face.Key-words: Seamless pipe; API 5L X65Q steel ...

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Effect of Different Cycles of Thermal Fatigue in Steel Metallurgical Aspects ASTM SA-516 Grade 60

Bicharra¹,

Medeiros²,

Biehl³

et al. 2020

American Journal of Engineering and Applied Sciences

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The ASTM SA-516 steel has applications in compact steam boilers of low and medium temperature and pressure. Deterioration can show when exposed to high temperatures due to fuel gases burning. Failures detected by inspections done in a frequency required by standard on the boilers. Among the main failure mechanisms found in materials used in boilers, creep, corrosion, when subjected to the action of the combustion gases or steam oxidation conditions, thermal fatigue and others can be mentioned. This work evaluates the effect of thermal fatigue in the metallurgical aspects of steel ASTM SA-516 grade 60. After the initial characterization of the steel checked that it heeds the specifications required by the standard, showing a microstructure of ferrite and perlite. The tests in heat transfer conditions produce temperatures between 750 to 850C on the surface, starting with an oxidizing flame produced by oxygen and acetylene gases. The cooling was by water, being the samples were submitted to several cycles of heating and cooling, causing thermal fatigue. After the tests, occurs the characterized of the samples through optical microscopy techniques, Scanning Electronic Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Vickers hardness and macrostructure analysis. ferrite, perlite colonies and no tempered martensite were the microstructures detected on the Heat-Affected Zone (HAZ). On substrate's region was not detected anisotropy or significant variations. When analyzing austenitic grain size was observed a refinement showing 12 ASTM grain size considered extra fine. The higher microhardness values occurred at the surface. The surface has had been affected by heat due to heating in intercritical and austenitization temperature and the cooling by water.

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Avaliação da Influência de Tratamentos Térmicos Pós-Soldagem Sobre a Microestrutura e Propriedades Mecânicas de Juntas de um Aço API 5L X70Q

Cited by 5 publications

References 2 publications

Evaluation of Microstructure and Mechanical Properties of Seamless Steel Pipes API 5L Type Obtained by Different Processes of Heat Treatments

Evaluation of Microstructure and Mechanical Properties of Seamless Steel Pipes API 5L Type Obtained by Different Processes of Heat Treatments

Características Microestruturais e Mecânicas ao Longo da Seção Transversal de Juntas Soldadas em Multipasses pelo Processo GMAW de um Aço API 5L X65Q

Effect of Different Cycles of Thermal Fatigue in Steel Metallurgical Aspects ASTM SA-516 Grade 60

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