Home » Boiler Tube Failure Handbook » Cracking » Not Near Weld » Longitudinal Observation: Cracking » Not Near Weld » Longitudinal Filter Items by: Observation Location Mechanism Appearance Observation Locations Mechanism Forming lap at tube OD Not in or near a weld » Cracking » Longitudinal Waterwall Material Defect Multiple tight fine cracks Longitudinal » Not in or near a weld » Cracking Superheater Stress Corrosion Cracking Fish-mouth opening Cracking » Longitudinal » Not in or near a weld Waterwall Hot Tensile Overload Short longitudinal cracks with numerous parallel cracks Not in or near a weld or attachment » Cracking » Longitudinal SuperheaterReheater Long-term Overheat/Creep Multitude of cracks parallel to tube Not in or near a weld or attachment » Cracking » Longitudinal Superheater Long-term Overheat/Creep Thick-lipped rupture and adjacent longitudinal fissuring Cracking » Longitudinal » Not Near Weld ReheaterSuperheater Creep Appearance Observation Location Mechanism