Although they provide essential services in a wide range of industries, submersible pumps are perhaps most commonly used to supply cooling water or circulate water. The main reason given for the failure of a submersible pump is usually corrosion, wear and component fracture. In addition, operating efficiency is greatly decreased once the vane wheel begins to corrode. Usually, it is said that "cavitation corrosion" and "abrasion corrosion" on the surface of the vane under conditions of high-speed rotation is the major corrosion behaviour. In studies by Sun Zhi, Wang Wenyin, Dong Xiaowen and LU Chengliang, the corrosion of the vane mainly appeared on the surface of the root and pilot column while there was less corrosion on the surface of the vane body. The electrochemical reactions behind this are analysed here, and the possible protective processes discussed.

To find an easier way to evaluate the cavitation erosion properties of materials, simple device was designed and developed by using high-pressure water jet. The new system generate cavitation erosion faster on the surface of tested sample. The cavitation behavior of Q235 steel (plain carbon steel, wt.% as following: 0.17 C, 0.43 Mn, 0.20 Si, 0.046 S, 0.007 P) has been studied in this system. The mass loss of the samples in rinsing water with time at normal temperature and the surface feature of test samples were obtained. The results show that this experimental system can produce cavitation quickly and efficiently. The cavitation damage of Q235 steel in rinsing water is a process from plastic damage to brittle damage. The cavitation erosion properties of variety materials and coatings can be studied with this system. The target distance and nozzle diameter play key role in the cavitation of metal in thesystem. There is a maximum cavitation rate when target distance S is about 40 mm under the test condition. The influence of highpressure water jet on the cavitation erosion behavior was discussed in the paper.