SAJNI

1. Metallurgical Aspects of Boiler Tube
Failures – A Few Case Studies

2. Metallurgical analysis
– Failure analysis
– Health/ Condition Assessment
– Residual Life Assessment
– Indegenisation / Material Development

3. Components
– Boiler tubes
– Turbine components
– High Energy Piping
– CHP Components
– Grinding elements
– Gas Turbine Components

4. Failure Mechanisms
(Water Touched Tubes)
Corrosion Fatigue
Flyash Erosion
Hydrogen Damage
Acid Phosphate corrosion
Caustic Gouging
Fireside Corrosion
Thermal Fatigue
Erosion Corrosion
Sootblower Erosion
Short Term Overheating
Low Temperature Creep
Chemical Cleaning Damage
Fatigue
Pitting
Coal Particle Erosion
Falling Slag Damage
Acid Dew Point Corrosion

5. Failure Mechanisms
(Steam Touched Tubes)
Long Term Overheating / Creep
Fire Side Corrosion
Dissimilar Metal Weld
Short Term Overheating
Stress Corrosion Cracking
SH/RH Sootblower Erosion
Fatigue
Rubbing Tubes / Fretting
Pitting
Graphitisation
SH /RH Chemical Cleaning

6. Stages in Failure Analysis
Visual Examination.
Collection of background
data.
Identification of sampling
locations.
Laboratory investigations
Analysis of data

7. Visual examination of damaged parts is the first
and most critical step in failure investigation

8. Case Studies in Failure
Investigation

9. Singarauli STPS
Boiler No.3
Date of Failure: 05/04/2004
Zone: Economiser Lower Bank
Location: Coil No.02
Material: SA210 A1
R&D Ref: 2210

12. Kahalgaon STPS
Boiler No.2
Date of Failure: 28/03/2004
Zone: Convection Pass Wall (RHS)
Location: Front Tube-01 (from RHS)
Material: C20
R&D Ref: 2209

16. Ramagundam STPS
Boiler No.1
Date of Failure: 01/03/2004
Zone: Economiser LHS wall
Location: Bank no.03 (from rear)
Material: SA210 A1
R&D Ref: 2198

19. Corrosion Fatigue

21. Ramagundam STPS
Boiler No.2
Date of Failure: 27/02/2004
Zone: Reheater
Location: Bank-05, Coil-22, Tube-07
Material: SA213 T22
R&D Ref: 2199

24. Korba STPS
Boiler No.1
Date of Failure: 09/01/2004
Zone: Reheater
Location: Panel-31, 3rd Bend, 2nd Bunch
Material: SA213 T11
R&D Ref: 2132

27. Long Term Overheating

28. Talcher #2, Stage –I
S-Panel Water Wall Tube Failure
Dated 09/01/2004
Report: R&D/MET/2130

29. Pinhole on weld

38. Vindhyachal #8
S-Panel Water Wall Tube Failure
Dated 06/12/2003
Report No R&D/MET/2073

41. 2073
Origin of Leak

42. Origin of Leak

46. NCPP Dadri #2
S-Panel Water Wall Tube Failure
Dated 05/11/2003
Report No. R&D/MET/R-2118

52. TANDA Unit #2
Hydrogen Damage Failure in Water Wall

56. NCPP Dadri Unit #2
Weld Porosity in Economiser Tube

60. Talcher Thermal Unit #6
Weld Defects in Economiser Tube

64. Water wall Tube (near Man hole)
Material: SA210 GrA1
Thermal Fatigue

65. Hydrogen Damage

66. Usefulness of Failure Analysis
Establishing the main reason of failure
Taking remedial action to prevent further
failures
Reduces forced outages
Helps in taking decisions for making design
modifications, if necessary