Which type of boiler tube damage is characterized by metal loss occurring in bands or stripes?

The type of boiler tube damage characterized by metal loss occurring in bands or stripes is circumferential grooving. This damage typically manifests as narrow grooves that run around the circumference of the tube, leading to an uneven wear pattern. Such grooves can significantly reduce the thickness of the boiler tubes and can be a result of factors such as erosion or cavitation, where steam bubbles form and then collapse, causing localized damage.

Understanding this type of damage is essential for maintenance and inspection of boilers, as it indicates wear that may lead to failures if not addressed. In contrast, the other types of damage listed do not involve the distinct banding effect: transverse cracks run perpendicular to the length of the tube, longitudinal cracks run parallel, and uniform thinning refers to a more consistent, even loss of material across the surface of the tube rather than localized, striped areas.