In the world of hydropower, maintaining the integrity of turbine components is crucial for efficient and reliable energy production. Stationary components, such as stay vanes, head covers, bottom rings, and scroll cases, are particularly vulnerable to erosion and corrosion, which can significantly impact their performance and lifespan. In this first part of our two-part blog series, we will explore how Resimac’s advanced protective coatings and repair solutions can effectively safeguard these critical components. 

Erosion and corrosion are major challenges in hydropower systems, especially in stationary components exposed to constant water flow and environmental elements. Erosion occurs due to the abrasive action of water carrying sediments, while corrosion results from chemical reactions between metal surfaces and water or other environmental agents. These processes can lead to material degradation, reducing the efficiency and reliability of turbines. 

To illustrate the practical applications and benefits of Resimac products in hydropower systems, let’s dive into five specific case examples where these advanced coatings and repair solutions have made a significant impact: 

• Situation: Leading edges of stay vanes often suffer from impact and erosion damage, necessitating rebuild and long-term protective coating. 

• Solution: Rebuild damaged sections with 101 Metal Repair Paste and protect with 202 Ceramic Repair Fluid. 

• Application Details: Repair area abrasive blast cleaned to SA2.5 with a 75-micron profile. Lost steel replaced with a layer of 101 Metal Repair Paste, cured for 2 hours, then machined back to a smooth finish. Two coats of 202 Ceramic Repair Fluid applied by brush at a nominal 300 microns per coat. 

• Situation: Internal surfaces of a Francis turbine head cover required refurbishment to protect against corrosion and abrasion. 

• Solution: Resurface with 202 Ceramic Repair Fluid. 

• Application Details: Internal plate face abrasive blast cleaned to SA2.5 with a 75-micron angular profile. Damaged sections rebuilt with a skim coat of 202 Fluid, followed by two more coats applied by brush at a nominal 300 microns per coat. 

• Situation: Large turbine throat ring requiring repair of wear and cavitation damage, with a protective coating to extend asset life and maintain unit efficiency. 

• Solution: Rebuild with 101 Metal Repair Paste and protect with 203 Superflow. 

• Application Details: Steel substrate abrasive blast cleaned to SA2.5 with a 75-micron profile. Pitted and damaged sections rebuilt with 101 Metal Repair Paste. Inlet and outlet points stripe coated, followed by two applications of 203 Superflow to a total dry film thickness of 500 microns. 

• Situation: Aged, corroded turbine in the Czech Republic needed rehabilitation to protect against future corrosion and wear. 

• Solution: Coat with Resichem 203 Superflow. 

• Application Details: Steel substrate abrasive blast cleaned to SA2.5 with a 75-micron profile. First coat of 203 Superflow applied by brush to entire surface to a nominal 250 microns. Second coat applied to high-wear sections to a nominal dry film thickness of 250 microns. 

Using Resimac’s protective coatings and repair solutions offers numerous benefits for hydropower customers: 

Protecting stationary components in hydropower systems against erosion and corrosion is essential for maintaining optimal performance and extending the lifespan of the equipment. Resimac’s advanced protective coatings and repair solutions provide effective and durable protection, ensuring that these components remain in excellent condition. 

For expert assistance in selecting the right Resimac grade for your specific application, contact Millstream Engineering today. Our team is ready to help you enhance the durability, cost-efficiency, and performance of your hydropower systems. 

Stay tuned for our next blog post, where we will focus on repairing rotating components damaged by cavitation and corrosion, featuring more case studies and application-specific examples.