Where is caustic embrittlement most frequently observed in boiler systems?

Caustic embrittlement is a specific phenomenon that occurs in boiler systems due to the concentration of caustic soda (sodium hydroxide) in water at specific points, usually under conditions of high temperature and pressure. It is most frequently observed at locations where the water is less than adequately treated, and the caustic concentration can increase, leading to the deterioration of steel.

In riveted joints below the water line, the conditions are conducive to caustic embrittlement. Water in these areas can become highly concentrated in caustic materials, especially if boiling occurs and there is a lack of adequate water circulation or treatment. The lower parts of the boiler, particularly where riveted joints exist, can experience stress and contribute to the deposition of alkaline substances, accelerating embrittlement.

Feedback regarding other options: The top of the boiler, while it may experience other types of stress or corrosion, is typically not where caustic embrittlement is most prevalent. Similarly, in the combustion chamber, conditions differ significantly due to heat and combustion gases rather than caustic buildup. The feedwater line may also not present the same localized concentration issues seen with riveted joints. Thus, the most appropriate scenario for observing caustic embritt