The effect of σ-phase precipitation at 800°C on the corrosion resistance in sea-water of a high alloyed duplex stainless steel

M.E. Wilms, V.J. Gadgil, J.M. Krougman, F.P. Ijsseling

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Super-duplex stainless steels are recently developed high alloyed stainless steels that combine good mechanical properties with excellent corrosion resistance. Because of a high content of chromium and molybdenum, these alloys are susceptible to σ-phase precipitation during short exposure to temperatures between 650 and 950°C. The effect of 800°C aging on σ-phase formation and on the mechanical properties of a super-duplex stainless steel have been reported previously by the authors.1 This investigation concerns the effect of σ-phase precipitation at 800°C on the corrosion behaviour in seawater and comprises anodic polarization scans and potentiostatic crevice corrosion tests. A serious deterioration of the corrosion resistance is found after aging times longer than 7 min, resulting in a drop of both the critical crevice corrosion temperature (CCT) and the breakdown potential (Ebd). The initiation of localized corrosion takes place next to the σ-phase, in the newly formed secondary austenite (γ2).
Original languageUndefined
Pages (from-to)871-881
Number of pages11
JournalCorrosion science
Issue number5
Publication statusPublished - 1994


  • METIS-128888
  • IR-24089

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