There is an increasing demand for Super 13% Cr (Super Martensitic Stainless Steel) tubing and casing (OCTG – Oil Country Tubular Goods), due to the material's superior strength and CO2 resistance, over conventional 13% Cr steel. Super 13% Cr combines low carbon content with increased Ni and Mo content, and particular heat treatment processes, in order to achieve its superior properties. To date, the literature available on this material is limited, with most articles concentrating on the explanation and remedies to major line-pipe failures that occurred on welds.

This paper summarizes tests to assess the role of chloride content in PH2S and pH testing solution. The negative effect of H2S saturation of the solution was observed, leading to a decrease of the passivation stage of the steel. Taking into account electrochemical parameters such as current densities and corrosion potentials, various environments (pH, chloride content and H2S) where SSC is likely to occur were investigated. The influence of the three parameters led to the creation of a 3-Dimensional mapping of SSC susceptibility with regard to the use of Super 13% Cr Stainless Steels. The Fit-For-Purpose philosophy of the new edition of NACE MR0175/ISO 15156 standard was used to develop this map.

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