Western Machine Works

Projects

Thermal Spray Repair – Wicket Gates


These wicket gates for a Northwest hydroelectric power plant needed repair. The wicket gate journals were out of OEM specifications and would be compromising the turbine’s long-term efficiency. Due to the weight of the wicket gates, our engineering team provided support with fixturing to ensure the equipment is safely secured in the lathe while turning at an optimal speed. After a thorough pre-machining setup and masking, the wicket gate journals were thermal sprayed using 420 stainless steel coating with up to 10,000 PSI bond strength. After-spray parameters were recorded and critical fits were restored back to OEM specifications.

Project:

  • Part: Wicket Gates
  • Details: 155″ Overall Length; 10,000 lbs.
  • Customer: Hydroelectric O&M Contractor

Challenges:

  • Required modification of counterbalance weight fixture to secure wicket gates safely in the lathe.
  • Upper journal fits on the wicket gates were out of OEM specifications.

Engineered Solutions:

  • Customize fixture and secure the wicket gate in the lathe.
  • Determine the most effective speed for uniform coating while keeping the wicket gate safely secured in the lathe while turning.
  • Prep and mask the wicket gate journal prior to blasting.
  • Blast fit on each wicket gate and record surface roughness.
  • Metallize wicket gate journals with 420 stainless steel to finish at 6.996″.
  • Record critical parameters after metallizing, including blast profile and maximum surface temperature.
  • Wrap wicket gates and secure for shipping in customer-supplied boxes.

Results:

  • Restored out-of-tolerance upper journal fits to OEM specifications.
  • Extend runnability and life of equipment by restoring critical surfaces through thermal spray.
  • Completed repair work within the production timeline.

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