Explanation

It is also called cavitation corrosion. The failure process of materials caused by the combined action of corrosion and cavitation. It often occurs in situations where high-speed fluid flows through complex metal surfaces and changes in liquid pressure, which can easily cause corrosion pits on the surfaces of steam turbine blades, marine propellers, pump impellers, and other surfaces. Bubbles are formed in the liquid when the absolute pressure in the local area of the fluid decreases to the vaporization pressure of the liquid. Bubbles burst when the liquid reaches the area with high pressure. At the same time, a large impact pressure is generated, which will damage the metal surface facial mask, cause plastic deformation or crack the brittle metal where the bubbles burst. Promotes decay and turbidity. Due to the synergistic effect of mechanical and chemical elements, corrosion pits are formed on the metal surface, which eventually leads to fatigue peeling. The preventive measures include: changing the design to reduce the hydrodynamic pressure difference in the process can reduce cavitation corrosion; Reasonable selection of materials and reduction of surface roughness reduce the probability of cavitation nucleation; Adopt rubber or plastics coating with high elasticity to absorb shock wave; Adopt cathodic protection.

Classification