Tecnologia em Metalurgia, Materiais e Mineração
https://tecnologiammm.com.br/article/doi/10.4322/2176-1523.20232879
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

Failure analysis of an AISI 316 steel pipe elbow exposed to the weather for three years after 16 years of operating at 515 °C

Análise de falha de uma curva de tubulação de aço AISI 316 exposta ao tempo por três anos após 16 anos operando a 515 °C

Flavio Pereira de Moraes; Emanuelle Machado Amaral; Flávio Beneduce Neto; Angelo Fernando Padilha

Downloads: 4
Views: 266

Abstract

The failure of an AISI 316 austenitic stainless-steel pipe used in a hydrotreatment plant was investigated. Circumferential cracks starting from outside the pipe and parallel to the weld were identified in the pipe elbow. The failure occurred after three years of plant inactivity and exposure to the atmosphere. The pipe was operated regularly for 16 years at a temperature of 515 °C before failure, having undergone phase transformations that made the steel susceptible to intergranular attack, followed by stress corrosion cracking at room temperature. The preferential precipitation of chromium-rich M23C6 carbides at the grain boundaries allowed the occurrence of sensitization, which, associated with the residual tensile stresses caused by the welding process and the presence of chlorine from industrial atmosphere concentrated under insulation, were responsible for the failure by stress corrosion cracking.

Keywords

AISI 316; Pipe elbow; Stress corrosion; Failure analysis

Resumo

Foi investigada a falha de um tubo de aço inoxidável austenítico AISI 316 utilizado em uma estação de hidrotratamento. Trincas circunferenciais partindo do lado externo em uma curva de tubulação e paralelas ao cordão de solda foram detectadas. A falha foi identificada após 3 anos de inatividade da instalação, exposta à atmosfera e temperatura ambiente. O tubo operou por 16 anos regularmente a 515 °C antes da falha, tendo sofrido transformações de fase que tornaram o aço suscetível ao ataque intergranular seguido de trincamento por corrosão sob tensão ao tempo na temperatura ambiente. A precipitação preferencial dos carbonetos ricos em cromo do tipo M23C6 nos contornos de grão foram responsáveis pela sensitização, que associada às tensões residuais de tração causadas pelo processo de soldagem e à presença de cloro proveniente da atmosfera industrial concentrado sob o isolamento térmico foram responsáveis pela falha por corrosão sob tensão.

Palavras-chave

AISI 316; Curva de tubulação; Corrosão sob tensão; Análise de falha

Referências

1 Staehle RW, Avery CH, Beachem CD, Bond AP, Boyd WK, Charley PJ, et al. Stress-corrosion cracking. In: Boyer HE, editor. Metals handbook ASM: failure analysis and prevention. Vol. 10. 8th ed. Ohio: ASM; 1975. p. 205-227.

2 Warke WR. Stress-corrosion cracking. In: Becker WT, Shipley RJ, editors. Metals handbook ASM: failure analysis and prevention. Vol. 11. Ohio: ASM; 2002. http://dx.doi.org/10.31399/asm.hb.v11.a0003553.

3 Pereira HB, Panossian Z, Baptista IP, Azevedo CRF. Investigation of stress corrosion cracking of austenitic, duplex and super duplex stainless steels under drop evaporation test using synthetic seawater. Materials Research. 2019;22(2):e20180211. http://dx.doi.org/10.1590/1980-5373-mr-2018-0211.

4 Thomas KC, Allio RJ. An integrated theory of stress corrosion. Nature. 1965;206(4979):82-83. http://dx.doi. org/10.1038/206082b0.

5 Thompson AW, Bernstein IM. The role of metallurgical variables in hydrogen-assisted environmental fracture. In: Fontana MG, Staehle W, editors. Advances in corrosion science and technology. 1st ed. New York: Springer; 1980. p. 53-175. http://dx.doi.org/10.1007/978-1-4615-9065-1_2.

6 Lu J, Hultman L, Holmström E, Antonsson KH, Grehk M, Li W, et al. Stacking fault energies in austenitic stainless steels. Acta Materialia. 2016;111:39-46. http://dx.doi.org/10.1016/j.actamat.2016.03.042.

7 Tian Y, Gorbatov OI, Borgenstam A, Ruban AV, Hedström P. Deformation microstructure and deformation-induced martensite martensite in austenitic Fe-Cr-Ni alloys depending on stacking fault energy. Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science. 2017;48(1):1-7. http://dx.doi.org/10.1007/s11661-016- 3839-2.

8 Harada K, Suzuki T, Ishi K. Applications of 18Cr-2Mo ferritic and high chromium ferritic/austenitic stainless steels in Japan. In: Barr RQ, editor. Stainless Steel’77. London: Amax Inc.; 1977. p. 177-184.

9 Gajjar PK, Khatri BC, Siddhpura AM, Siddhpura MA. Sensitization and desensitization (healing) in austenitic stainless steel: a critical review. Transactions of the Indian Institute of Metals. 2022;75(6):1411-1427. http://dx.doi. org/10.1007/s12666-021-02439-8.

10 Nuthalapati S, Kee KE, Pedapati S. Detection and characterization of chloride induced stress corrosion cracking on SS304 under perlite thermal insulation. Materials Research Proceedings. 2023;29:456-471. http://dx.doi. org/10.21741/9781644902516-52.

11 Abou-Elazm A, Abdel-Karim R, Elmahallawi I, Rashad R. Correlation between the degree of sensitization and stress corrosion cracking susceptibility of type 304H stainless steel. Corrosion Science. 2009;51(2):203-208. http://dx.doi. org/10.1016/j.corsci.2008.10.015.

12 Martorano MA, Tavares CF, Padilha AF. Predicting delta ferrite content in stainless steel castings. ISIJ International. 2012;52(6):1054-1065. http://dx.doi.org/10.2355/isijinternational.52.1054.

13 Santos FAM, Martorano MA, Padilha AF. Delta ferrite formation and evolution during slab processing from an 80-ton industrial heat of AISI 304 austenitic stainless steel. REM - International Engineering Journal. 2023;76(1):47- 54. http://dx.doi.org/10.1590/0370-44672022760001.

14 Padilha AF, Plaut RL, Rios PR. Annealing of cold-worked austenitic stainless steels. ISIJ International. 2003;43(2):135-143. http://dx.doi.org/10.2355/isijinternational.43.135.

15 Berger A, Egels G, Fussik R, Benito SM, Weber S. A new approach to the optimization of the austenite stability of metastable austenitic stainless steels. Journal of Materials Engineering and Performance. 2023;32(20):9244-9252. http://dx.doi.org/10.1007/s11665-023-08066-2.

16 Weiss B, Stickler R. Phase instabilities during high temperature exposure of 316 austenitic stainless steel. Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science. 1972;3:851-866.

17 Lai JKL. A study of precipitation in AISI type 316 stainless steel. Materials Science and Engineering. 1983;58(2):195-209. http://dx.doi.org/10.1016/0025-5416(83)90046-0.

18 Minami Y, Kimura H, Ihara Y. Microstructural changes in austenitic stainless steels during long-term aging. Materials Science and Technology. 1986;2(8):795-806. http://dx.doi.org/10.1179/mst.1986.2.8.795.

19 Padilha AF, Rios PR. Decomposition of austenite in austenitic stainless steel. ISIJ International. 2002;42(4):325- 327. http://dx.doi.org/10.2355/isijinternational.42.325.

20 National Institute of Materials Science. Creep data sheet. metallographic atlas of long-term crept materials, no. M-2: micrographs and microstructural characteristics of crept specimens of 18Cr-12Ni-Mo stainless steel for boiler and heat exchanger seamless tubes (SUS 316H TB). Japan: NIMS; 2003.

21 Moraes FP, Alves SF Jr, Plaut RL, Padilha AF. Degradation of microstructure and properties of an AISI 316L steel pipe after more than 100,000 hours usage at 640 °C in a petrochemical industry. Procedia Structural Integrity. 2019;17:131-137. http://dx.doi.org/10.1016/j.prostr.2019.08.018.

22 Chen Y, Wei S, Wu D, Lu S. Mechanism of δ-ferrite decomposition in high Si-bearing austenitic stainless steel weld metal during aging at 550 °C. Materials Science and Engineering A. 2023;876:145163. http://dx.doi.org/10.1016/j. msea.2023.145163.

23 American Society for Testing and Materials. ASTM E165/E165M-18: standard practice for liquid penetrant testing for general industry. West Conshohocken: ASTM; 2018. 19 p.

24 American Society for Testing and Materials. ASTM A262-15: standard practices for detecting susceptibility to intergranular attack in austenitic stainless steels. Reapproved. West Conshohocken: ASTM; 2021. 20 p.

25 Barsoum Z, Lundbäck A. Simplified FE welding simulation of fillet welds: 3D effects on the formation residual stresses. Engineering Failure Analysis. 2009;16(7):2281-2289. http://dx.doi.org/10.1016/j.engfailanal.2009.03.018.

26 Berkane R, Gachon JC, Charles J, Hertz J. A thermodynamic study of the chromium-carbon system. Calphad. 1987;11(4):375-382. http://dx.doi.org/10.1016/0364-5916(87)90035-6.

27 Sinha AK, Buckley RA, Hume-Rothery W. Equilibrium diagram of the iron–molybdenum system. Journal of the Iron and Steel Institute. 1967;205:191-195.

28 Yakel HL. Atom distributions in sigma phases. I. Fe and Cr atom distributions in a binary sigma phase equilibrated at 1063, 1013 and 923 K. Acta Crystallographica. Section B, Structural Science. 1983;39(1):20-28. http://dx.doi. org/10.1107/S0108768183001974.

29 Deighton M. Solubility of M23C6 in type 316 stainless steel. Journal of the Iron and Steel Institute. 1970;208:1012- 1014.


Submetido em:
15/05/2023

Aceito em:
04/09/2023

654e6762a9539527026a3c82 tmm Articles
Links & Downloads

Tecnol. Metal. Mater. Min.

Share this page
Page Sections