Which type of damage can cause localized pitting in boiler tubes?

Which type of damage can cause localized pitting in boiler tubes?

• A. Dissolved oxygen
• B. High pressure
• C. Thermal shock
• D. Mechanical stress

Answer: (A)

Localized pitting in boiler tubes often results from the presence of dissolved oxygen in the water. When oxygen is present in the boiler water, it can lead to corrosion, specifically a form known as oxygen pitting. This happens because dissolved oxygen can react with the metal of the boiler tubes, creating small cavities or pits due to localized electrochemical reactions. Over time, these pits can reach a depth that compromises the structural integrity of the tubing, leading to failures or leaks. In contrast, high pressure generally affects the overall stress levels within the boiler system but does not specifically cause pitting. Thermal shock refers to the rapid temperature changes that can occur during operation and may lead to cracking or other types of structural failure rather than pitting. Mechanical stress can contribute to wear and tear but is more related to fatigue or deformation, which would not specifically cause localized pitting like dissolved oxygen does. Understanding the impact of dissolved oxygen on corrosion processes is crucial for maintaining boiler integrity and longevity.

Localized pitting in boiler tubes often results from the presence of dissolved oxygen in the water. When oxygen is present in the boiler water, it can lead to corrosion, specifically a form known as oxygen pitting. This happens because dissolved oxygen can react with the metal of the boiler tubes, creating small cavities or pits due to localized electrochemical reactions. Over time, these pits can reach a depth that compromises the structural integrity of the tubing, leading to failures or leaks.

In contrast, high pressure generally affects the overall stress levels within the boiler system but does not specifically cause pitting. Thermal shock refers to the rapid temperature changes that can occur during operation and may lead to cracking or other types of structural failure rather than pitting. Mechanical stress can contribute to wear and tear but is more related to fatigue or deformation, which would not specifically cause localized pitting like dissolved oxygen does. Understanding the impact of dissolved oxygen on corrosion processes is crucial for maintaining boiler integrity and longevity.