Question 196Steam Plants - 1st Asst/Chief70% to pass
The formation of a pit in the surface of a boiler tube is most likely to occur when _______________.
AI Explanation
The correct answer is D) the tube metal acts as an anode.
The formation of a pit in the surface of a boiler tube is most likely to occur when the tube metal acts as an anode in an electrochemical corrosion process. This happens when there are differences in the electrical potential between the tube metal and other materials, causing the tube metal to be preferentially corroded. This type of localized corrosion, known as pitting, can lead to the formation of pits or holes in the tube surface.
The other options are incorrect because, while dissolved minerals, waterside deposits, and sludge can contribute to overall corrosion, they do not directly cause the formation of pits in the same way as electrochemical corrosion with the tube metal acting as an anode.
Related Questions
#194 Boiler tube failures can result from _______________.#195 In a water-tube boiler, waterside scale formation is caused by _______________.#197 Fireside burning of boiler tubes is usually the direct result of _______________.#198 Cratering and water tracking in boiler tubes is caused by _______________.#199 When the rate of heat transfer through tube walls is so reduced that the metal becomes overheated, which of the following conditions will result in the boiler?