Which damage is indicated by abnormal cratering at the ends of tubes?

Abnormal cratering at the ends of tubes is directly indicative of cratering damage. Cratering typically occurs when localized overheating or excessive wear leads to the material being eroded or pitted away, creating depressions or 'craters' at the site of damage. This type of damage can commonly be observed in heat exchangers or boiler tubes where there are issues with heat transfer, leading to thermal stress concentrations.

The recognition of cratering is crucial for maintenance and operational reliability since it can signal underlying problems that may lead to more extensive damage if not addressed. By pinpointing the presence of cratering damage, maintenance teams can take appropriate corrective actions to prevent failure, enhance performance, and ensure the longevity of the equipment involved.