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  • 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.

    Waleed Khalifa
    Principal and CEO
    Arabic Consultancy Center for Engineering Materials, Inspection
    Maadi, Cairo
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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.

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

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