What factor is critical in assessing vessels for caustic embrittlement?

The factor that is critical in assessing vessels for caustic embrittlement is the temperature and stress level. Caustic embrittlement is a form of cracking that occurs in carbon steel when it is exposed to caustic soda solutions at elevated temperatures, particularly in the presence of residual stresses. Higher temperatures can exacerbate the embrittlement process, while the stress level in the material—stemming from factors such as operational loading, previous fabrication processes, or corrosion-related degradation—can make the material more susceptible to cracking.

Understanding the interplay between temperature and stress is essential for predicting the likelihood of caustic embrittlement, enabling inspectors and engineers to make informed decisions about the integrity and safety of pressure vessels. This consideration allows for proper maintenance strategies and inspections aimed at identifying potential weaknesses that could lead to failure, ensuring the continued safe operation of vessels that handle caustic materials.