Where is caustic embrittlement most likely to occur?

Caustic embrittlement is a specific type of stress corrosion cracking that occurs in certain circumstances, particularly in environments where caustic agents (such as sodium hydroxide) are present. This phenomenon is more likely to happen in areas that experience high stress, which can be the result of mechanical loads or residual stresses from manufacturing processes, such as welding.

In high-stress areas, microcracks can form and propagate over time when influenced by the presence of caustic substances. These areas provide a more conducive environment for the embrittling effects of caustic agents to take place, as the stress can exacerbate the material's susceptibility to cracking. Thus, it is crucial to monitor and evaluate stress levels in pressure vessels to mitigate the risk of caustic embrittlement occurring.

In contrast, while other factors like low temperatures, locations at joints or welded areas, and above liquid levels also pose potential risks for pressure vessels, they do not specifically create the environment that is most closely associated with the occurrence and severity of caustic embrittlement as high stress does.