Boiler Tube Failure Investigation
CORE SERVICE OFFERINGS

Boiler Tube Failure

Boiler tubes

can undergo sudden failures by rupture or leakage and is usually detected while in operation rather than during a hydro test or other inspection activities. This calls for immediate action as it can often cause a shutdown of the boiler, leading to loss of production and downtime. It is critical to understand the various modes and mechanisms of the boiler components such as tubes, headers, pipes, turbines, etc. A proper understanding of the damage mechanisms, the inspection activities, and on-line monitoring tools are necessary to address challenges in a more systematic manner.

Metallurgical root-cause investigation helps narrow down the reasons for failure and provides inputs to take the right corrective action. TCR has extensive experience in undertaking complex failures of boiler tube, turbine shaft & blades and has helped many power plants and utility boiler users to solve their problems.

Boiler Tube Failure
Brief classification of frequently encountered causes of

Boiler tube failure

FLUID SIDE CORROSION

  • Oxygen pitting
  • Under deposit corrosion-caustic gouging
  • Under deposit corrosion-hydrogen damage
  • Under deposit corrosionphosphate corrosion
  • Acid cleaning corrosion
  • Internal deposit/corrosion product build up fireside wastage
  • Flow accelerated corrosion

FIRESIDE CORROSION OF SUPER HEATER AND REHEATER TUBING

  • Fireside oxidation
  • Fly ash corrosion
  • Soot blower erosion
  • Coal particle corrosion
  • Steam impingement

FIRESIDE CORROSION OF WATERWALL TUBING

  • Erosion
  • Low temperature (dew point) fireside corrosion
  • Falling slag damage
  • Tube rubbing

RUPTURE

  • Short-term overheating (stress rupture)
  • Long-term overheating (creep rupture)

METALLURGICAL DEGRADATION

  • Graphitization
  • Sigma phase embrittlement cracking

CORROSION WITH METALLURGICAL ASPECT

  • Dissimilar metal weld stress rupture
  • Stress-corrosion cracking
  • Stress induced corrosion
  • Polythionic Acid Stress Corrosion cracking

FATIGUE

  • Corrosion fatigue-waterside
  • Corrosion fatigue-fireside
  • Thermo mechanical fatigue
  • Vibration fatigue