Stainless steels stress-corrosion cracking, hydrogen

Wilde, B. E. and Kim, C. D., The R61e of Hydrogen in the Mechanism of Stress-corrosion Cracking of Austenitic Stainless Steel in Hot Chloride Media , Corrosion, 28, 350 (1972) Lin, F. and Hochman, R. F., Electrochemical Study of Stress-corrosion Cracking of Ti 8-1-1 Alloy and NaCl Solutions , Corrosion, 28, 182 (1972)... 

The above simple concepts need to be modified and expanded to allow discussion of stress-corrosion cracking of stainless steels in general, especially as the role of hydrogen in assisting crack growth must be accounted for. 

Sodium hydroxide, even at low concentrations, will cause stress corrosion cracking in stainless steel when subjected to temperatures above 100°C. Caustic solutions are much better handled in alloys with high concentrations of nickel, such as Alloy 400 or Alloy 600. Alloy 400 has also found success in applications involving fluoride, hydrogen fluoride, and hydrofluoric c dP ... 

Unless heavily cold worked, the austenitic stainless steels are resistant to hydrogen stress cracking such as that caused by hydrogen sulfide. They are also resistant to hydrogen embrittlement caused by phenomena other than cathodic charging. If sensitized, austenitic stainless steels can also be susceptible to intergranular corrosion. 

With the desired microstructure, these alloys are resistant to hydrogen stress cracking and much more resistant to chloride stress corrosion cracking than are the austenitic stainless steels. (The threshold temperature for chloride stress corrosion cracking of duplex alloys in neutral pH aqueous chlorides is about 300°F [150°C].) The chloride stress corrosion cracking resistance of the duplex alloys is similar to that of superaustenitic alloys such as Alloy AL-6XN. Because they contain about 50% ferrite, the duplex stainless steels are more susceptible to hydrogen embrittlement. 

R. Liu, N. Narita, C. Alsteter, H. Birnbaum, E.N. Pugh, Studies of the orientations of fracture surfaces produced in austenitic stainless steels by stress-corrosion cracking and hydrogen embrittlement, MetaH. Trans. A llA (1980) 1563-1574. 

O.M. Alyousif, R. Nishimura, Stress corrosion cracking and hydrogen embrittlement of sensitized austenitic stainless steels in boiling samrated magnesium chloride solutions, Corros. Sci. 50 (2008) 2353-2359. 

Austenitic stainless steels are sensitive to stress corrosion cracking in chloride-containing environments (Chapter 11). On the other hand, they are generally more resistant to hydrogen embrittlement than ferritic stainless steels. 

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