Application of modified low carbon (LC) martensitic stainless steels in the oil and gas industry is not only restricted to subsea flowlines, but is planned to be extended also to the topside equipment of production units. Since no service experience of such materials is available so far, the sour service tolerance of two typical LC 13 % Cr steels with different nickel and molybdenum contents has been investigated at free corrosion by the slow strain rate test (SSRT), predominantly in the state as
delivered. For basic information on hardening. effects by welding, also a simple quenching procedure was applied to another test series. As a result, the nickel and molybdenum richer material maintained its sour service resistance at different pH and H2S levels in the NACE TM 0177-
96 standard solution also in the quenched condition. The lower alloyed steel exhibited an increasing susceptibility to sulfide stress cracking in the quenched condition, as compared to the as delivered state.
Keywords: hydrogen absorption, sulfide stress corrosion cracking, low carbon martensitic stainless steel, slow strain rate test, free corrosion