Corrosion and cavitation protection of steel hydroelectric station structures and equipment

Abstract

Steel structures and equipment of hydroelectric stations, constantly or periodically operating in water, at places with a highhumidity, and in the open air under atmospheric effects -hydraulic turbines, penstocks, surge tanks, gates and emergency gates, trash racks, auxiliary equipment with pipelines and fittings, etc. -constitute a considerable part of the productive resources of hydropower engineering. The total weight of steel in structures at hydroelectric stations amounts to about 1.5 million tons, including more than 0.3 million tons in turbines. Protection of steel structures against damage by corrosion and cavitation is an important economic problem.An increase in the service life of steel structures is an important factor in the economy of maintenance and operating expenses at hydroelectric stations, not oaly as a consequence of the direct reduction in steel consumption but also as a consequence of the reduction in labor costs, since work on the protection and restoration of structures subjected to corrosion and cavitation number among the heaviest and most labor-consuming repair operations performed at hydroelectric stations.The following methods are used for protecting steel structures against corrosion: use of resistant metals and alloys, isolation of the surfaces being protected from the external corrosive environment (organic. metallized, and other coatings), and electrochemical protection.