KEPCO Journal on Electric Power and Energy

Korea Electric Power Corporation (한국전력공사)
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Investigation of the Contributions of Creep and Thermal Fatigue to Failure of a High-Intermediate Pressure Steam Turbine Casing

  • Lee, Jaehong (KEPCO Research Institute, Korea Electric Power Corporation) ;
  • Jung, Nam-gun (KEPCO Research Institute, Korea Electric Power Corporation)
  • Received : 2019.08.06
  • Accepted : 2019.11.15
  • Published : 2020.03.30
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Abstract

The contribution of damage mechanisms to failure of steam turbine casing made of Cr-Mo-V steel was investigated. Creep-fatigue interaction on the HP side corner of turbine casing was revealed as the root cause of the catastrophic failure performed by metallurgical analysis. The steady-state pressure and transient thermal stress were analyzed based on the actual operating condition of the thermal plant. Damage of creep-fatigue interaction to crack initiation was evaluated with multiaxial effects. The contribution ratio of creep and fatigue to the crack initiation was estimated to 3:1. Temporary geometrical correct action with repair weld was executed. For long-term operation, design improvement of casing equipment for creep resistance should be needed.

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References

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