Method for spraying surface treatment of boiler water wall

       Boiler water wall spraying is generally divided into three steps: surface pretreatment, surface purification and surface roughening (or activation).



1. Surface preprocessing:



One is to make the surface of the workpiece suitable for coating deposition and increase the bonding area;



The second is to help overcome the shrinkage stress of the coating. Some parts of the workpiece are pretreated accordingly to disperse the local stress of the coating and improve the shear resistance of the coating. Common methods are cutting fillets and pre-coated grooves. Rough threading is also one of the commonly used methods, especially when spraying large workpieces, cutting threads are usually used to increase the combined area.



2. Surface purification:

Usually solvent cleaning, lye cleaning, heating, degreasing and other methods are used to remove the surface oil and keep it clean. Commonly used cleaning solvents are: gasoline, acetone, carbon tetrachloride and alkene trichloride. Lye is often used for large repair workpieces. Lye is usually made from sodium hydroxide or sodium carbonate, which is a cheaper method.

3. An important pretreatment method for sandblasting and roughening.



Sandblasting can form a uniform, uneven rough surface on the cleaned surface, which is conducive to the mechanical bonding of the coating. The clean sandblasted workpiece surface is driven by clean compressed air, which can generate compressive stress on the surface of the substrate, remove the surface oxide film, and cause lattice distortion of part of the surface metal, which is conducive to the physical bonding of the coating. Base metals can be cleaned, rough, highly reactive surfaces after blasting.



The reliability of boiler water-cooled wall tubes directly affects the safe and effective operation of power plant units, but in fact, water-cooled wall tubes will inevitably be corroded and worn, thereby reducing their effective bearing capacity and safety. The surface spraying method can effectively improve the corrosion resistance of water-cooled wall tubes of thermal power plant boilers, save maintenance costs, reduce operating costs, and increase the service life of water-cooled wall tubes. Surface spray method is a very reliable method to solve the corrosion and wear of thermal power plant boilers. High temperature corrosion and wear of boiler water wall tubes has always been a common serious problem in power systems. Its direct harm is mainly reflected in the following two aspects, which make the pipe wall thin; the water wall has a sudden pipeline explosion accident.



To sum up, spraying protection for water-cooled wall spraying manufacturers is a very important thing, and we also need to pay attention to its maintenance in order to make it run better.