Avaliação da possibilidade de aplicação de tratamentos térmicos de múltiplas normalizações como mecanismo de refino microestrutural e incremento de propriedades mecânicas em aços API-OCTG
Evaluation of multiple normalizing heat treatments as mechanism of microstructural refinement and mechanical properties improvement in API-OCTG steels
José Márcio da Rocha, Junia Ananias, Geraldo Lúcio de Faria
Resumo
Os aços API-OCTG graus K55 e T95 são importantes materiais de engenharia atualmente especificados para fabricação de tubos sem costura para aplicação nos processos de extração de óleo e gás. Considerando a crescente demanda destes produtos com cada vez melhores relações entre resistência mecânica e tenacidade ao impacto, este trabalho se propôs a investigar os efeitos de tratamentos térmicos de múltiplas normalizações sobre a evolução microestrutural e as propriedades mecânicas de dois aços com composições químicas que atendem os requisitos dos referidos graus. Simulações termodinâmicas computacionais e ensaios dilatométricos foram utilizados para se determinar temperaturas críticas de austenitização e a susceptibilidade à formação de carbonetos nos aços estudados. Sucessivos tratamentos térmicos de normalização foram planejados e executados. Por meio da aplicação de técnicas de caracterização microestrutural (MEV-STEM) e de ensaios mecânicos de dureza, tração e impacto Charpy, mostrou-se que os tratamentos térmicos de múltiplas normalizações tiveram efeito positivo sobre o refino microestrutural dos dois aços. Os efeitos mais significativos foram observados até o segundo ciclo de normalização, sendo pequenas as diferenças microestruturais e de propriedades mecânicas entre o segundo e o terceiro ciclo. O efeito das múltiplas normalizações foi mais pronunciado para o grau T95, onde a diminuição do tamanho de grão austenítico prévio, as redistribuições de soluto e de precipitados propiciaram melhoria significativa das propriedades mecânicas.
Palavras-chave
Abstract
The API-OCTG steels grades K55 and T95 are important engineering materials specified, nowadays, as raw-material for the manufacturing of seamless pipes used in oil and gas extraction processes. Considering the growing demand for these products with increasingly better mechanical strength and impact toughness ratio, this work proposed to investigate the effects of multiple normalizing heat treatments on the microstructural evolution and mechanical properties of two steels with chemical compositions that meet the requirements of the abovementioned grades. Computational thermodynamic simulations and dilatometric tests were carried out to determine critical austenitizing temperatures and the steel susceptibility to carbide formation. Successive normalizing heat treatments were planned and executed. Applying microstructural characterization techniques (MEV-STEM) and mechanical tests (hardness, tensile test, Charpy impact test), it was shown that multiple normalizing heat treatments had a positive effect on the microstructural refining of the both studied steels. The most significant effects were observed until to the second normalizing cycle. There were not great differences between microstructure and mechanical properties measured for the second and the third cycles. This effect was more pronounced for grade T95, where the decrease of the previous austenitic grain size, solute and precipitate redistributions provided significant improvements in mechanical properties.
Keywords
References
1 Agência Nacional do Petróleo, Gás Natural e Biocombustíveis – ANP. Anuário Estatístico Brasileiro do Petróleo, Gás Natural e Biocombustíveis 2021. Brasília: ANP; 2021 [acesso em 15 out 2021]. Disponível em: https://www.gov.br/anp/pt-br/centrais-de-conteudo/publicacoes/anuario-estatistico/anuario-estatistico-2021
2 Morais JM. Petróleo em águas profundas: uma história tecnológica da Petrobras na exploração e produção offshore. Brasília: IPEA; 2013 [acesso em 20 out 2021]. Disponível em: https://www.ipea.gov.br/portal/index.php?option=com_content&view=article&id=18251
3 Godefroid LB, Sena BM, Trindade VB. Evaluation of microstructure and mechanical properties of seamless steel pipes API 5L type obtained by different processes of heat treatments. Materials Research. 2017;20(2):514-522.
4 Gray JM, Siciliano F. High strength microalloyed linepipe: half a century of evolution. Houston: Microalloyed Steel Institute; 2009. p. 20-45.
5 American Petroleum Institute – API. API-5L: Specification for Line Pipe. 46th ed. Washington: APA; 2018.
6 American Petroleum Institute API. API-5CT: Specification for casing and tubing. 10th ed. Washington: APA; 2018.
7 Souza WM, Itman A Fo, Silva RV, Martins JBR, Lima LXC. The effects of auto-tempering martensite on mechanical strength of a microalloyed steel containing boron and titanium. Tecnologica em Metalurgia, Materiais e Mineração. 2020;17(4):e2198.
8 Liu M, Wang CH, Dai YC, Li X, Cao GH, Russel AM, et al. Effect of quenching and tempering process of sulfide stress cracking susceptibility in API-5CT-C110 casing steel. Materials Science and Engineering A. 2017;688:378-387.
9 Shin SY, Woo KJ, Hwang B, Kim S, Lee S. Fracture-Toughness Analysis in Transition-Temperature Region of Three American Petroleum Institute X70 and X80 Pipeline Steels. Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science. 2009;40(4):867-876.
10 Godefroid LB, Cândido LC, Toffolo RB, Barbosa LH. Microstructure and mechanical properties of two API steels for iron ore pipelines. Materials Research. 2014;17(Suppl 1):114-120.
11 Gray JM, Siciliano F. High strength microalloyed linepipe: half a century of evolution. Houston: Microalloyed Steel Institute; 2009. p. 20-45.
12 Larzabal G, Isasti N, Rodriguez-Ibabe JM, Uranga P. Evaluating strengthening and impact toughness mechanisms for ferritic and bainitic microstructures in Nb, Nb-Mo and Ti-Mo microaaloyed steels. Metals. 2017;7(2):65.
13 Hu J, Liu Y, Wang G, Li Q. Effects of microstructure on the low-temperature toughness of an X80 x D1422mm heavy-wall heat-induces seamless bend. Metals. 2021;11:1055.
14 Muniz TF, Trindade VB, de Faria GL. Heat Treatments of a microalloyed Low Carbon Steel (Oil and Gas Industry). In: Associação Brasileira de Engenharia e Ciências Mecânicas. Proceedings of the 23rd ABCM International Congress of Mechanical Engineering; 2015 December 6-11; Rio de Janeiro, RJ, Brazil. Rio de Janeiro: ABCM.
15 Kaijalainen AJ, Suikkanen PP, Limnell TJ, Karjalainen LP, Komi JI, Porter DA. Effect of austenite grain structure on the strength and toughness of direct-quenched martensite. Journal of Alloys and Compounds. 2013;577:S642-S648.
16 Xiong X, Yang F, Zou X, Suo J. Effect of twice quenching and tempering on the mechanical properties and microstructures of SCRAM steel for fusion application. Journal of Nuclear Materials. 2012;430:114-118.
17 Khani Sanij MH, Ghasemi Banadkouki SS, Mashreghi AR, Moshrefifar M. The effect of single and double quenching and tempering heat treatments on the microstructure and mechanical properties of AISI 4140 steel. Materials & Design. 2012;42:339-346.
18 Liu J, Yu H, Zhou T, Song C, Zhang K. Effect of double quenching and tempering heat treatment on the microstructure and mechanical properties of a novel 5Cr steel processed by electro-slag casting. Materials Science and Engineering A. 2014;619:212-220.
19 Chang E, Chang CY, Liu CD. The effects of double austenitization on the mechanical properties of a 0.34C containing low-alloy Ni-Cr-Mo-V steel. Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science. 1994;25:545-555.
20 Andrés CG, Caballero FG, Capdevila C, Álvares LF. Application of dilatometric analysis to the study of solid-solid phase transformations in steels. Materials Characterization. 2002;48:101-111.
21 Rodrigues K, Faria GL. Characterization and prediction of continuous cooling transformations in rail steels. Materials Research. 2021;24(5):e20200519.
22 ASTM International. ASTM E3. Standard Guide for Preparation of Metallographic Specimens. West Conshohocken, PA: ASTM International; 2017.
23 ASTM International. ASTM E112. Standard Test Methods for Determining Average Grain Size. West Conshohocken, PA: ASTM International; 2013.
24 Ali M, Porter D, Kömi J, Eissa M. El faramawy H. The effect of double austenitization and quenching on the microstructure and mechanical properties of CrNiMoWMnV ultrahigh-strength steels after low-temperature tempering. Materials Science and Engineering A. 2019;763:138169.
25 Zheng Y, Wang F, Li C, Lin Y, Cao R. Effect of martensite structure and carbide precipitates in mechanical properties of Cr-Mo alloy steel with different cooling rate. High-Temperature Materials and Processes. 2019;38:113-124.
26 ASTM International. ASTM E384. Standard Test Method for Microindentation Hardness of Materials. West Conshohocken, PA: ASTM International; 2017.
27 ASTM International. ASTM E8. Standard Test Methods for Tension Testing of Metallic Materials. West Conshohocken, PA: ASTM International; 2021.
28 ASTM International. ASTM A370. Standard Test Methods and Definitions for Mechanical Testing of Steel Products. West Conshohocken, PA: ASTM International; 2020.
29 ASTM International. ASTM E23. Standard Test Methods for Notched Bar Impact Testing of Metallic Materials. West Conshohocken, PA: ASTM International; 2018.
30 Rodrigues KF, Mourão GMM, Faria GL. Kinetics of isothermal phase transformations in premium and standard rail steels. Steel Research International. 2020;92(2):2000306.
31 Cirimello PG, Otegui JL, Carfi G, Morris W. Failure and integrity analysis of casings used for oil well drilling. Engineering Failure Analysis. 2017;75:1-14.
32 Aranda MM, Kim B, Rementeira R, Capdevila C, García de Andrés C. Effect of prior austenite grain size on pearlite transformation in a hypo-eutectoid Fe-C-Mn steel. Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science. 2014;45:1778-1786.
33 Sarikaya M, Steinberg BG, Thomas G. Optimization of Fe/Cr/C base structural steels for improved strength and toughness. Metallurgical Transactions. A, Physical Metallurgy and Materials Science. 1982;13:2227-2237.
34 Papaefthymiou S, Bouzouni M, Petrov RH. Study of carbide dissolution and austenite formation during ultra-fast heating in medium carbon chromium molybdenum steel. Metals. 2018;8:646.
35 Lee J, Lee T, Mun D, Bae CM, Lee CS. Comparative study on the effects of Cr, V, and Mo carbides for hydrogenembrittlement resistance of tempered martensitic steel. Scientific Reports. 2019;9:5219.
Submitted date:
11/22/2021
Accepted date:
06/15/2022
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