Avaliação do desempenho dos aços inoxidáveis AISI316l e superdúplex AISI F53 quanto à corrosão em frestas

Abstract:

This paper presents the results of tests conducted with the objective of verifying the crevice corrosion resistance of austenitic stainless steel AISI 316L stainless steel and AISI superduplex F53. Specific tests were conducted which tried to simulate two situations corrosion of a system for offshore extraction of crude oil, namely external corrosion and internal corrosion of these systems. In the case of external corrosion, the exposure was through a synthetic sea water with bubbling atmospheric air, which aimed to simulate corrosion under the condition of immersion in seawater not deep, where sea water is aerated due to very waves and ripples. In the case of internal corrosion, means were exposure to synthetic sea water by injecting carbon dioxide (CO₂) and a solution of 100,000 ppm of Cl-ions by injecting a gas mixture consisting of 93% CO₂ and 7% hydrogen sulfide (H^₂S). Additionally, tests were carried out in the field with exposure of specimens in the laboratory installed floating in São Sebastião and standardized tests such as the test for determining the critical temperature of crack ASTM G 48 and electrochemical tests in accordance with ASTM G 61. Assays immersion in sea water, both in laboratory (synthetic sea water) and field (natural seawater) showed that the stainless steel AISI 316L austenitic stainless steel and AISI superduplex F53 are susceptible to crevice corrosion, and susceptibility highly dependent on the surface finish.


Reference:
PANOSSIAN, Z; VARGAS, C.P; MATOS, R.B; ALMEIDA, N.L; PIMENTA, G.S. Avaliação do desempenho dos aços inoxidáveis AISI 316l e superdúplex AISI F53 quanto à corrosão em frestas. In: CONFERÊNCIA SOBRE TECNOLOGIA DE EQUIPAMENTOS,.COTEQ, 11., 2011, Porto de Galinhas. Anais…