INFLUÊNCIA DO TRATAMENTO TÉRMICO PÓS-SOLDAGEM NA DUREZA DA ZTA DO AÇO 9%Ni

O sistema de reinjeção de CO2 nas camadas do pré-sal aumenta significativamente a produtividade dos poços e pode atingir a temperatura de -95°C na rápida descompressão em caso de falha. Como o sistema está sujeito a condições altamente corrosivas, a soldagem de revestimento dos tubos de aço 9% Ni com superliga de níquel pelo processo GTAW está sendo estudada. Segundo estudos prévios, o tratamento térmico pós-soldagem (TTPS) é recomendado devido a alta dureza da ZTA. Porém, estudos conforme a norma ASTM A333 grau 8 não atingiram os níveis desejados de dureza. Neste trabalho foram analisados TTPS’s em distintas condições de temperatura e tempo, procurando identificar a que melhor atende à aplicação. Após 40 condições de tratamentos testadas, ensaios de dureza e caracterização por microscopia, verificou-se que a mínima dureza ocorre na condição de duas camadas de revestimento tratada à 600°C por 4h, devido à microestrutura similar ao metal base composta por matriz ferrítica com austenita reversa nos contornos de grãos

microstructure evolution during heat treatments

Funding Information: Authors acknowledge the Portuguese Fundação para a Ciência e a Tecnologia (FCT – MCTES) for its financial support via the project UID/EMS/00667/2019 (UNIDEMI). JPO acknowledges funding by national funds from FCT - Fundação para a Ciência e a Tecnologia, I.P., in the scope of the projects LA/P/0037/2020 , UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication – i3N. Funding of CENIMAT/i3N by national funds through the FCT-Fundação para a Ciência e a Tecnologia, I.P., within the scope of Multiannual Financing of R&D Units, reference UIDB/50025/2020–2023 is also acknowledge. FWCF acknowledges Fundação para a Ciência e a Tecnologia ( FCT-MCTES ) for funding the Ph.D. Grant 2022.13870. BD. The authors acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Beamtime was allocated for proposal I-20210986 EC. The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. This activity has received funding from the European Institute of Innovation and Technology (EIT) Raw Materials through the project Smart WAAM: Microstructural Engineering and Integrated Non-Destructive Testing. YZ acknowledges the National Natural Science Foundation of China ( 51601091 ), the Natural Science Foundation of Jiangsu Province ( BK 20160826 ), the Six Talent Peaks Project of Jiangsu Province ( 2017-XCL-051 ), the Fundamental Research Funds for the Central Universities ( 30917011106 ), and Key Research and Development Plan of Jiangsu Province ( BE 2020085 ). Funding Information: Authors acknowledge the Portuguese Fundação para a Ciência e a Tecnologia (FCT – MCTES) for its financial support via the project UID/EMS/00667/2019 (UNIDEMI). JPO acknowledges funding by national funds from FCT - Fundação para a Ciência e a Tecnologia, I.P. in the scope of the projects LA/P/0037/2020, UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication – i3N. Funding of CENIMAT/i3N by national funds through the FCT-Fundação para a Ciência e a Tecnologia, I.P. within the scope of Multiannual Financing of R&D Units, reference UIDB/50025/2020–2023 is also acknowledge. FWCF acknowledges Fundação para a Ciência e a Tecnologia (FCT-MCTES) for funding the Ph.D. Grant 2022.13870. BD. The authors acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Beamtime was allocated for proposal I-20210986 EC. The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. This activity has received funding from the European Institute of Innovation and Technology (EIT) Raw Materials through the project Smart WAAM: Microstructural Engineering and Integrated Non-Destructive Testing. YZ acknowledges the National Natural Science Foundation of China (51601091), the Natural Science Foundation of Jiangsu Province (BK 20160826), the Six Talent Peaks Project of Jiangsu Province (2017-XCL-051), the Fundamental Research Funds for the Central Universities (30917011106), and Key Research and Development Plan of Jiangsu Province (BE 2020085). Publisher Copyright: © 2023 The Author(s)The study reports that the combined use of in situ interlayer hot forging and post-deposition heat treatment (PDHT) could alter the typical coarse and oriented microstructure of the Ni-based superalloy 625 obtained by arc plasma directed energy deposition (DED) to a fine and non-oriented condition. In situ synchrotron X-ray diffraction and electron backscatter diffraction showed that the high-temperature (1100 °C/ 1 h) PDHT induced significant recrystallization, leading to grain refinement and low texture index, while partially dissolving deleterious Laves and δ phases. Low-temperature (980 °C/ 1 h) PDHT had a limited effect on the grain size refinement and induced the formation of secondary phases. It is shown that conventional heat treatments applied to Ni-based superalloy 625 obtained by arc plasma DED are not conducive to optimized microstructure features. In situ hot forging induced enough crystal defects to promote static recrystallization during PDHT. Besides, high-temperature PDHT met the AMS 5662 grain size requirements.publishersversionpublishe

process development and microstructure effects

JPO acknowledges funding by national funds from FCT - Fundação para a Ciência e a Tecnologia, Portugal, I.P. in the scope of the project LA/P/0037/2020. The authors acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Beamtime was allocated for proposal I-20210986 EC. This activity has received funding from the European Institute of Innovation and Technology (EIT) Raw Materials through the project Smart WAAM: Microstructural Engineering and Integrated Non-Destructive Testing. YZ acknowledges the National Natural Science Foundation of China (51601091), the Natural Science Foundation of Jiangsu Province (BK 20160826), the Six Talent Peaks Project of Jiangsu Province (2017-XCL-051), the Fundamental Research Funds for the Central Universities (30917011106), and Key Research and Development Plan of Jiangsu Province (BE 2020085). Funding Information: Authors acknowledge the Portuguese Fundação para a Ciência e a Tecnologia (FCT – MCTES) , Portugal, for its financial support via the project UID/EMS/00667/2019 (UNIDEMI). JPO acknowledges funding by national funds from FCT - Fundação para a Ciência e a Tecnologia, Portugal, I.P., in the scope of the projects LA/P/0037/2020 , UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication – i3N. FWCF acknowledges Fundação para a Ciência e a Tecnologia ( FCT-MCTES ), Portugal, for funding the Ph.D. Grant 2022.13870. BD . The authors acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Beamtime was allocated for proposal I-20210986 EC. The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. This activity has received funding from the European Institute of Innovation and Technology (EIT) Raw Materials through the project Smart WAAM: Microstructural Engineering and Integrated Non-Destructive Testing. YZ acknowledges the National Natural Science Foundation of China (51601091), the Natural Science Foundation of Jiangsu Province (BK 20160826), the Six Talent Peaks Project of Jiangsu Province (2017-XCL-051), the Fundamental Research Funds for the Central Universities (30917011106), and Key Research and Development Plan of Jiangsu Province (BE 2020085). Publisher Copyright: © 2023 The AuthorsThe typical as-built coarse and cube-oriented microstructure of Inconel® 625 parts fabricated via arc-based directed energy deposition (DED) induces anisotropic mechanical behavior, reducing the potential applications of arc-based DEDed Inconel® 625 in critical components. In this sense, the present work aimed to reduce the grain size and texture by applying an in situ interlayer hot forging (HF) combined with post-deposition heat treatments (PDHT). The produced samples were characterized through optical microscopy, scanning electron microscopy coupled with electron backscatter diffraction, synchrotron X-ray diffraction, and Vickers microhardness. Also, a dedicated deformation tool was designed and optimized via a finite element method model considering the processing conditions and thermal cycle experienced by the material. It is shown that the in situ interlayer deformation induced a thermo-mechanical-affected zone (dynamic recrystallized + remaining deformation, with a height of ≈ 1.2 mm) at the bead top surface, which resulted in thinner aligned grains and lower texture index in relation to as-built DED counterpart. In addition, the effects of solution (1100 °C/ 1 h) and stabilization (980 °C/ 1 h) PDHTs on the Inconel® 625 HF-DEDed parts were also analyzed, which promoted fine and equiaxed static recrystallized grains without cube orientation, comparable to wrought material. Therefore, the HF-DED process significantly refined the typical coarse and highly oriented microstructure of Ni-based superalloys obtained by arc-based DED.publishersversionpublishe

Ultrasonic Inspection of a 9% Ni Steel Joint Welded with Ni-based Superalloy 625: Simulation and Experimentation

The ultrasonic inspection of thick-walled welded joint with austenitic weld metal has proven to be a challenge due to its anisotropic microstructure that can promote ultrasonic waves attenuation. This work aimed to optimize the phased array ultrasonic inspection of the thick-walled joint of a 9% Ni steel pipe welded with Ni-based superalloy 625. The development was carried out by CIVA numeric simulation to preview the beam behavior during the inspection of GTAW (Gas Tungsten Arc Welding)/SMAW (Shielded Metal Arc Welding) joint with anisotropic weld metal. To validate the simulation results, experimental tests were performed with a phased array transducer using longitudinal waves on a calibration block withdrawn from the joint. The configuration of low frequency (2.25 MHz), 16 active elements and a scanning angle of 48° ensured the inspection of the entire joint and the computational simulation proved to be essential for the success of the inspection

Utilização de um sistema ultra-sônico para medida de tensão

Relata um primeiro teste com uma sistema ultra-sônico que foi montado no laboratório da SUMET (IEN), onde se pretende desenvolver estudos de medidas de tensões internas em materiais através da técnica ultra-sônica do tempo decorrido. Nele é mostrado o comportamento das ondas ultra-sônicas, longitudinal e cisalhante, ao atravessarem um aço submetido à tração uniaxial. Mostra-se que o sistema funciona com eficiência sendo capaz de realizar medidas de tensão em materiais

Avaliação Por Ultra-Som De Tratamento Térmico De Alívio De Tensões Em Componente Industrial

Os processos de fabricação normalmente introduzem tensões internas nos materiais, tornando muitas vezes necessária, por isso, a realização de tratamento térmico de alívio de tensões (TTAT) em estruturas ou componentes. Esses tratamentos térmicos são conduzidos sob rigoroso controle da temperatura e do tempo, porém seus resultados nem sempre são avaliados, seja por motivos técnicos ou financeiros. A técnica ultra-sônica desponta, assim, como uma ferramenta promissora na avaliação de TTAT. Nesse trabalho foram medidos os tempos de percurso de ondas ultra-sônicas em pontos próximos a um cordão de solda de uma câmara hiperbárica de aço de alta resistência, de 170mm de espessura, bem como de uma peça de referência. Esses testes ultra-sônicos foram realizados antes e após um TTAT. Os resultados comprovaram que o ultra-som é bastante eficiente na avaliação do TTAT, pois é uma técnica de inspeção rápida e não destrutiva, e que ele poderia, inclusive, servir de ferramenta na determinação do menor tempo e da menor temperatura de TTAT capazes de proporcionar o alívio de tensões desejado, reduzindo, assim, o consumo de energia.Usually, residual stresses arise in structural components as a consequence of fabrication processes, for which, in many occasions, is necessary to perform a stress relief heat treatment (SRHT). These treatments are carried out under rigorous control of time and temperature, but their results are rarely evaluated due to technical or economical reasons. On this context, ultrasound comes as a promising tool to evaluate SRHT. In this work was measured the time of flight of ultrasonic waves applied near a weld of a hyperbaric chamber made of high strength 170 mm thick steel plate, as well as on a reference specimen. These tests were performed previous to and after a SRHT. Results prove ultrasound to be quite efficient on the evaluation of this SRHT, since it is a fast and non destructive technique, which might even be used to define the optimum time and temperature of treatment, thus reducing energy consumption

Avaliação de tensões internas por ultra-som usando a técnica da birrefri

Neste trabalho é avaliado o estado de tensão em um corpo-de-prova em aço, composto por um disco maciço e um chapa quadrada com um furo central, de dimensões geométricas tais que tensões residuais internas são geradas quando de sua montagem. A partir dos valores da constante acustoelástica do material, das birrefringências nos componentes (situação sem tensão) e das birrefrigências no corpo-de-prova montado (situação com tensão) foi determinada a tensão residual nos pontos selecionados, alcançando um valor máximo de 311 MPa para a diferença entre as tensões principais. Foi investigado também, na avaliação das tensões residuais, o impacto do uso do valor médio da distribuição da birrefringência inicial em lugar dos valores locais. Os resultados obtidos nesse segundo caso mostraram que a diferença das tensões principais atingiu um valor máximo de 291 MPa, sendo porém de 12% a variação média entre as duas formas de cálculo. Os resultados experimentais foram comparados com um cálculo analítico aproximado da diferença das tensões principais no corpo-de-prova montado, assumindo-se condições de isotropia e homogeneidade material, obtendo-se uma boa concordância entre eles

Avaliação por ultra-som do tratamento térmico para alívio de tensões em aço

Os processos de fabricação geram tensões internas nos materiais. A área nuclear usa critérios rígidos de aceitação obrigando que em muitos materiais utilizados em estruturas e componentes sejam realizados tratamentos térmicos para alívio de tensões. Esses tratamentos são feitos com bastante controle. Entretanto, a preocupação com a segurança nuclear é cada vez maior. Este trabalho propõe um método não destrutivo por ultra-som para avaliar o alívio de tensões realizado garantindo assim a eficiência desses tratamentos. Foi utilizada uma barra de aço jateada, contendo tensões trativas e compressivas, e o método mostrou-se bastante eficaz