The susceptibility of a martensitic stainless steel to hydrogen cracking and the lack of such susceptibility in an austenitic stainless steel has been pointed out previously.1-3 In general, cathodic polarization is found to cause or stimulate hydrogen cracking of susceptible metals. Stress corrosion cracking (SCC), on the other hand, usually responds to anodic polarization and is inhibited by cathodic polarization; furthermore, complete cathodic protection is effective below a well defined critical potential (e.g., stainless steels4-6 ) or within a critical potential range (e.g., carbon steels in alkaline solutions7 ).
However, for a stressed, high strength 0.4% C low alloy steel, Yamaoka and Wranglen8 demonstrated that both anodic and cathodic polarization in aqueous media induced cracking. Wilde9 recently reported similar dual behavior of a high strength martensitic stainless steel, and ascribed the observed failures in both instances to hydrogen cracking. Anodic polarization in an NaCl solution,...
