A critical review of the literature has been undertaken to establish the current state of knowledge and understanding of the corrosion and stress corrosion cracking (SCC) of 13 wt-%Cr martensitic stainless steels for applications in the oil and gas industry. Corrosion data for 13%Cr martensitic stainless steels are critically evaluated to establish the conditions in which the various steels are in the active state, pitting or passive state. There is evidence that as welded specimens have poorer pitting resistance at ambient temperatures than at elevated temperatures owing to the formation of an oxidised layer, perhaps depleted in chromium. Data for hydrogen uptake and diffusivity in 13%Cr steels are reviewed. The results suggest that incorporation of Mo in the steel reduces the subsurface hydrogen content when the steel is in the active state, suggesting repressed dissolution kinetics. The data in the literature on SCC of modi ed 13%Cr steels indicate that increasing the temperature at pH values where pitting is the precursor to cracking decreases the susceptibility to sulphide stress cracking. Whilst a matching weld ller would be expected to be more susceptible to hydrogen embrittlement because of a higher hardness of the weld metal relative to the duplex stainless steel ller, there is limited evidence to suggest that welds with matching llers are more resistant to cracking than welds with duplex llers. The heat affected zone of a duplex weld appears to be more susceptible to pitting than for a matching ller. Evidence of intergranular SCC from the root of a girth weld at 110°C has been obtained but is eliminated by post-weld heat treatment. Nevertheless, this is an important observation and needs further investigation. CEST/2031The authors are in FOREWORDThe terms conventional, modi ed, alloyed and super 13 wt-%Cr weldable steels are used as material descriptors in the literature. (All compositions in this paper are given in wt-% unless otherwise speci ed.) Conventional steels will be assumed to include ferritic stainless steels such as AISI 420 and also AISI 410, which has a slightly lower C content. Modi ed, alloyed and super 13%Cr weldable steels are often used for similar material speci cations as there appears no consistent de nition. Lean (1 . 0 -2 . 5Ni, 51Mo), medium (2 . 5 -4 . 5Ni, 1 . 0 -2 . 0Mo) and fat (4 . 5 -6 . 5Ni, 42Mo) have also been proposed as a means of distinguishing grades. When citing speci c publications, the terms used therein will be employed. Otherwise, modi ed, alloyed and super terms will be assumed to be interchangeable but the Mo content should be apparent. Where the text refers to very low carbon 13%Cr steels with no signi cant Mo additions this will be clearly distinguished.The units of pressure adopted in the literature vary considerably, with bar, atm, psi, and MPa all used. To assist comparison, all pressures in this text will be expressed in MPa but the relationship to other units is listed in the Appendix.The pH value of pure water decreases with increase in temperature. W...

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