The anti-corrosion measures for wind yaw systems mainly include the following:
1、 Material selection
Choose corrosion-resistant materials: In the manufacturing process of yaw system components, priority should be given to materials with good corrosion resistance. For example, for key components such as yaw gears, stainless steel materials are used. Stainless steel contains alloying elements such as chromium and nickel, which can form a dense oxide film on the surface of the material, preventing corrosive media such as oxygen and moisture from contacting the internal metal, thereby effectively resisting corrosion. Like 304 stainless steel, its chromium content is about 18% -20% and nickel content is about 8% -10.5%. It has good corrosion resistance in general atmospheric environments and certain oceanic climate conditions.
Surface coating material: For some components that cannot be entirely made of corrosion-resistant materials, high-performance anti-corrosion coatings are used. Like epoxy zinc rich primer, it is based on epoxy resin and contains a large amount of zinc powder. The electrode potential of zinc is lower than that of iron. In a corrosive environment, zinc powder will be corroded first, thus protecting the steel substrate. Meanwhile, epoxy resin has good adhesion and chemical corrosion resistance, which can effectively prevent the invasion of corrosive media such as moisture and salt.
2、 Surface treatment technology
Mechanical treatment: Clean the surface through mechanical treatment methods such as sandblasting and shot blasting before component installation. Sandblasting is the use of high-speed sand flow to clean and roughen the surface of the substrate, resulting in a certain degree of roughness on the surface. This can enhance the adhesion of subsequent coatings and remove impurities such as rust and oxide scale on the surface, reducing corrosion sources. Shot blasting is the process of using a shot blasting device to rapidly project projectiles onto the surface of components, achieving the same cleaning and roughening effect.
Chemical treatment: Chemical treatment methods such as phosphating and passivation are used. Phosphating treatment is the process of placing metal components into a solution containing phosphoric acid, phosphates, and other components, forming a protective layer of phosphate on the metal surface. This film can improve the corrosion resistance of metal surfaces and serve as a good bottom layer for paint coatings, enhancing the adhesion between the coating and the substrate. Passivation treatment mainly uses chemical agents to form a passivation film on the metal surface. For example, after nitric acid passivation treatment, the corrosion resistance of the surface of stainless steel parts will be significantly improved.
3、 Sealing protection
Sealing design: Provide good sealing design for key parts of the yaw system, such as yaw motors, gearboxes, etc. Use high-quality seals such as rubber seals. Rubber sealing rings can effectively prevent external impurities such as rainwater and dust from entering the internal structure. Taking the lip seal ring as an example, it forms a seal by tightly adhering the lip to the rotating shaft or joint surface, which can block external moisture and corrosive particles.
Protective casing: Install protective casing for the entire yaw system or some critical subsystems. The shell can be made of metal or composite materials, and the surface of the shell is generally treated with anti-corrosion measures such as painting or galvanizing. The protective shell can physically isolate the yaw system from harsh external environments, reducing the likelihood of corrosion.
4、 Maintenance measures
Regular inspection and cleaning: Regularly inspect the yaw system for signs of corrosion, such as rust spots on the surface of components and peeling of coatings. At the same time, use appropriate cleaning agents to clean the surface of the components from pollutants such as oil, dust, and salt. For example, wind turbines in coastal areas require more frequent cleaning of yaw system components due to the high salt content in the air to prevent salt accumulation and corrosion.
Timely repair of damaged coatings: Once any damage is found to the coating, such as scratches, peeling, etc., it should be repaired in a timely manner. Surface treatment such as grinding, rust removal, etc. can be carried out on the damaged area first, and then the anti-corrosion coating that is the same or compatible with the original coating can be reapplied to ensure that the anti-corrosion performance of the component is restored.