Chlorides, stress-corrosion cracking combinations resulting

Another specific version of stress corrosion cracking results from a chloride concentration cell. It is sometimes referred to as chloride embrittlement and can affect stainless steels. For the problem to appear a combination of local chloride concentration and transgranular cracking occurs, leading ultimately to metal failure. 

Metallic chloride salts, such as ferric chloride and cupric chloride, can be very corrosive to CF8M. Above 160°F (71°C), chloride can also cause SCC. The combination of chlorides, water, oxygen, and surface tensile stress can result in cracking at stresses far below the tensile strength of all austenitic SSTs. Although a threshold chloride level may exist, one is difficult to set because chlorides concentrate in pits, crevices, and under deposits until the minimum concentration is reached. One must be concerned about SCC any time a few hundred ppm chlorides is present and the temperature exceeds about 160°F (71 °C). SCC may develop at lower temperatures if the pH is low. 

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