Hydropower Plants
Cavitation/erosion protection, blade profile restoration and shaft/bearing surface renewal for Francis, Pelton and Kaplan turbine components.
In short: In hydropower plants, turbine runners, nozzles and blades are damaged by sediment-laden water erosion and cavitation. UMEK applies HVOF carbide coatings and weld restoration to Francis, Kaplan and Pelton turbine components.
Application Areas
Our Solutions for Hydropower
- HVOF coatings for turbine runners
- WC-Co-Cr wear-resistant coatings
- Cr₃C₂-NiCr coatings
- Cavitation and erosion protection
- Stainless steel weld restoration
- Rebuilding of blade profiles
- Shaft and bearing surface restoration
- Precision grinding and surface finishing
- On-site or in-workshop refurbishment of turbine components
Typical Causes of Wear in Hydropower Plants
Sediment erosion
Sand and silt particles in the water wear runner and nozzle surfaces at high velocity.
Cavitation
The collapse of vapour bubbles formed by pressure fluctuations causes pitting on the surface.
Profile loss
Changes in blade and nozzle profiles reduce turbine efficiency.
Which Part, Which Problem, Which Method?
| Part / equipment | Typical damage | Method considered |
|---|---|---|
| Francis / Kaplan runners and blades | Erosion, cavitation | Weld restoration and HVOF carbide coating |
| Pelton nozzles and needles | Sediment erosion | HVOF WC-CoCr coating |
| Guide vanes and gates | Erosion, loss of sealing | HVOF coating, precision machining |
| Draft tube and other surfaces | Cavitation damage | Weld repair and protective coating |
The method for each part is finalised through engineering evaluation of the operating conditions, base material and extent of damage. At our facility in Ankara, application and final grinding are carried out in the same workflow.
Read Before You Decide
About Hydropower Plants
How is cavitation damage on a turbine runner repaired?
Damaged areas are built up with a suitable weld filler, the profile is machined and, where required, the surface is protected with an HVOF carbide coating. The method depends on the depth of the damage.
Which coating is used for Pelton nozzles and needles?
Tungsten carbide based coatings applied by HVOF are commonly considered for protection against sediment erosion; for details, see our article on HVOF thermal spray.
Can a preliminary assessment be made from a photo of the damage?
Yes. A preliminary engineering assessment is made from photos and dimensions of the part; scope and lead time are confirmed after this assessment.
Do You Have a Project in the Hydropower Industry?
Send us your part's technical details and we will prepare a quotation with engineering evaluation within 24-48 hours.