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Failures of Duplex Stainless Steel, Solutions Out of the Box

  • 1.  Failures of Duplex Stainless Steel, Solutions Out of the Box

    Posted 08-26-2020 10:28
    Duplex stainless steel pipe and flange conforming to ASTM A790 2507 and ASTM A182 F51, failed after two years of service. It was a multiphase flow of natural gas, condensate and water. The conditions were severe: salinity was 12% and temperature was 57 to 75 C. The ferrite % in the weld root was low: 30-25% in some locations. The failures are seen in the attachments. Both damages occur at the 6 o'clock position.  Installing dehydration units, as a remedy, seems impractical at this stage. I would appreciate if you can share some or your ideas and experience for solutions, solutions out of the box.

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    Waleed Khalifa
    Principal and CEO
    Arabic Consultancy Center for Engineering Materials, Inspection
    Maadi, Cairo
    01098163293
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  • 2.  RE: Failures of Duplex Stainless Steel, Solutions Out of the Box

    Posted 08-27-2020 12:18
    Something has adversely impacted the corrosion resistance of super duplex SS.  In the past, I have seen degradation of corrosion resistance due to the formation of sigma phase due to poor manufacturing. I would expect low ferrite number in the welds to result in cracking problems.

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    Robert Franco
    President
    Franco Corrosion Consulting, LLC
    Bellaire TX
    (713) 304-0398
    RobertFranco
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