|
Bulging tube adjacent to field weld |
Bulging » Deformation
|
Waterwall |
Long-term Overheat |
|
Metal thinning on fireside |
Deformation » Thinning
|
WaterwallSuperheater |
Smelt/Slag Attack |
|
External wastage beneath adherent slag deposit |
Deformation » Thinning
|
WaterwallSuperheater |
Corrosion From Slag Attack |
|
External thinning, smooth areas |
Deformation » Thinning
|
Reheater |
Fireside Corrosion/Erosion |
|
Smooth surface |
Deformation » Thinning
|
ReheaterSuperheater |
Fly Ash Erosion |
|
General pitting |
Holes, Pits, Gouges » Waterside (Firetube boiler)
|
Waterside of firetube boiler |
Acid Attack |
|
ID pitting with corrosion tubercles |
Holes, Pits, Gouges » Waterside
|
WaterwallReheaterSuperheater |
Oxygen Pitting |
|
sharply defined hole |
Holes, Pits, Gouges » Waterside
|
Economizer |
Corrosion Fatigue |
|
Severe corrosion on side of tube facing gas turbine/duct burners |
Holes, Pits, Gouges » Waterside
|
Evaporator Section |
Multiple Under-Deposit Corrosion Mechanisms Including Caustic Gouging, Phosphate Attack, and Hydrogen Damage |
|
Undercut corrosion, multi-color deposits (red, white, black). (This is a view of a tube ID following cleaning.) |
Holes, Pits, Gouges » Waterside
|
Waterwall |
Acid Phosphate Attack |
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Thinning on inside of a U-bend or other change in direction |
Holes, Pits, Gouges » Waterside
|
Economizer |
Flow Accelerated Corrosion (FAC) |
|
Defect at weld bar attachment |
Holes, Pits, Gouges » Fireside/Material Flaw
|
Waterwall |
Weld/Materials Defect |
|
Porosity in weld |
Holes, Pits, Gouges » Material Defect
|
Superheater |
Weld Defect |
|
Thinning from the fireside, pockmarks on external surface |
Holes, Pits, Gouges » Fireside
|
Waterwall |
Fireside Corrosion |
|
Metal wastage |
Holes, Pits, Gouges » Fireside
|
Waterwall |
Fireside Corrosion |
|
Catastrophic failure associated with weld overlay |
Cracking » In or near weld or attachment » Transverse
|
Waterwall |
Hydrogen Damage |
|
Fine cracks around studs |
Cracking » Transverse » Not in or near a weld
|
Studded Waterwall |
Thermal Fatigue |
|
Circumferential cracking |
Cracking » Transverse » Not in or near a weld or attachment
|
Waterwall |
Thermal Fatigue |
|
Forming lap at tube OD |
Cracking » Longitudinal » Not in or near a weld
|
Waterwall |
Material Defect |
|
Multiple tight fine cracks |
Cracking » Longitudinal » Not in or near a weld
|
Superheater |
Stress Corrosion Cracking |
|
Fish-mouth rupture |
Cracking » Not in or near a weld
|
ReheaterSuperheater |
Short-Term Overheat |
|
Fish-mouth opening |
Cracking » Longitudinal » Not in or near a weld
|
Waterwall |
Hot Tensile Overload |
|
Thick-lipped rupture, may be very large window missing or a flap hanging by one edge |
Holes, Pits, Gouges
|
Waterwall |
Hydrogen Damage |
|
Irregular cracking |
Cracking » Not in or near a weld
|
Superheater |
Creep |
|
Short longitudinal cracks with numerous parallel cracks |
Cracking » Longitudinal » Not in or near a weld or attachment
|
ReheaterSuperheater |
Long-term Overheat/Creep |
|
Multitude of cracks parallel to tube |
Cracking » Longitudinal » Not in or near a weld or attachment
|
Superheater |
Long-term Overheat/Creep |
|
Longitudinal crack at bend |
Cracking » Not in or near a weld or attachment
|
WaterwallReheaterSuperheater |
Long-term Overheat |
|
Transverse cracking in the rolled portion of tube where it is inserted into the drum |
Near or in weld or attachment
|
Riser tube at rolled connection in drum |
Caustic Induced Stress Corrosion Cracking |
|
Complete failure at weld |
Cracking » In or near weld or attachment » Transverse
|
Superheater |
Thermal FatigueDissimilar Metal Weld Creep |
|
Transverse crack near support |
Cracking » In or near weld or attachment » Transverse
|
Evaporator |
Thermal Fatigue |
|
Brittle fracture in heat affected zone of a weld |
Cracking » In or near weld or attachment » Transverse or Random
|
ReheaterSuperheater |
Graphitization |
|
Multiple cracks associated with attachment on outside of tube |
Cracking » In or near weld or attachment » Longitudinal or Random
|
WaterwallEconomizer |
Corrosion Fatigue |
|
Longitudinal ID corrosion-fatigue cracks |
Cracking » In or near weld or attachment » Longitudinal
|
Waterwall |
Corrosion Fatigue |
|
Longitudinal cracks adjacent to weld |
Cracking » In or near weld or attachment » Longitudinal or Random
|
Superheater |
Wrong material/Creep |
|
Thick-lipped rupture and adjacent longitudinal fissuring |
Cracking » Longitudinal » Not Near Weld
|
ReheaterSuperheater |
Creep |
|
Deformation and perforation from the outside in |
Holes, Pits, Gouges » Fire/Gas Side
|
Reheater |
Mechanical damage |
|
Complete weld separation |
Cracking » In or near weld or attachment » Transverse
|
Superheater |
Dissimilar Metal Weld Failure (DMW) |
|
Cracks close to attachments |
Cracking » In or near weld or attachment » Longitudinal
|
Waterwall |
Corrosion Fatigue |
|
Severe corrosion gouging at a weld-backing ring |
Holes, Pits, Gouges » Water/Steam Side
|
Waterwall |
Caustic Gouging |
|
Severe pock-marked corrosion on fireside |
Holes, Pits, Gouges
|
Furnace Riser |
Corrosion/Thermal Fatigue |
|
Bulging tube adjacent to field weld |
Bulging » Deformation
|
Waterwall |
Long-term Overheat |