Umbilicals are one application where superduplex stainless steel tubing is used. The umbilical is used for controlling sub-sea wellhead functions using hydraulic lines as well as for power supply and chemical injection. The most commonly used grade is 25Cr Superduplex, however, a new superduplex stainless steel, SANDVIK SAF 2906, was introduced on the market in 2005. Santos developed the offshore Casino gas field located off shore in Victoria in Australia in 2005 using subsea wells and since January 2006 have been producing through a subsea pipeline. An electro-hydraulic multi-core umbilical controls the subsea wells. SANDVIK SAF 2906 tubes were selected for the umbilical. The most important corrosion aspect for an umbilical is the resistance of the superduplex stainless steel tubing to crevice corrosion in seawater. The two parameters controlling the corrosivity of seawater against crevice corrosion are the potential and the temperature. The severity of a crevice depends on several factors such as the material of the crevice former and the geometry of the crevice. Temperature and potential design curves representing initiation of corrosion have been widely used to illustrate the resistance against pitting or crevice corrosion in . seawater. During the project a comprehensive crevice corrosion testing programme was performed to ensure the fitness for service of the umbilical. Testing in ferric chloride solution, ASTM G48, and electrochemical test methods, stepped potential tests in synthetic sea water and 28 day potentiostatic tests with in simulated sea water, were performed on parent and weld materials. The results of the tests indicated that the umbilical is fit-for service when the entire design of the umbilical is taken into account. In addition to the laboratory testing crevice corrosion testing has been performed in natural seawater of seamless superduplex tubes of SANDVIK SAF 2507 and SANDVIK SAF 2906. The test program was carried out with representative crevice condition for an umbilical in natural seawater with different temperatures and potentials and the results are presented as design curves. Similar crevice corrosion resistance as inducated by design curves were obtained for SANDVIK SAF 2906 and SANDVIK SAF 2507.


    Zugriff

    Zugriff über TIB

    Verfügbarkeit in meiner Bibliothek prüfen


    Exportieren, teilen und zitieren



    Titel :

    Crevice corrosion testing of Sandvik SAF 2906 and design curves of superduplex stainless steels in seawater representing umbilicals


    Weitere Titelangaben:

    Spaltkorrosionsprüfung beim Stahl Sandvik SAF 2906 und Bemessungskurven für Versorgungsleitungen aus nichtrostendem Superduplexstahl in Meerwasser


    Beteiligte:
    Kivisäkk, Ulf (Autor:in) / Novak, Pavel (Autor:in) / Moss, Harry (Autor:in)


    Erscheinungsdatum :

    2007


    Format / Umfang :

    13 Seiten, 5 Bilder, 3 Tabellen, 8 Quellen


    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch





    Influence of artificial seawater on the cyclic response of superduplex stainless steels

    Girones, A. / Llanes, L. / Anglada, M. et al. | Tema Archiv | 2005


    Nr. 2906

    DataCite | 1901



    Mechanism of dissimilar metal crevice corrosion of superferritic stainless steels

    Salamat, G. / Juhl, G.A. / Kelly, R.G. | Tema Archiv | 1995