Chloride Stress Corrosion Cracking (Stainless Steel) By yaang.com

Chloride stress corrosion involves selective attack of the metal along grain boundaries. In the formation of the stainless steel, a chromium-rich carbide precipitates at the grain boundaries leaving these areas low in protective chromium, and thereby, susceptible to attack. It has been found that this is closely associated with certain heat treatment resulting from welding.  This can be minimized considerably by proper annealing processes. 

This form of corrosion is controlled by maintaining low chloride ion and oxygen content in the environment and the use of lowcarbon stainless steel. Environments containing dissolved oxygen and chloride ions can readily be created in auxiliary water systems.  Chloride ions can enter these systems via leaks in condenser or at other locations where auxiliary systems associated with the nuclear facility are cooled by unpurified cooling water. Dissolved oxygen can readily enter these systems with feed and makeup water. Thus, chloride stress corrosion cracking is of concern, and controls must be used to prevent its occurrence.

Source: Yaang Pipe Industry Co., Limited (www.yaang.com)