The Effects of the Frequency and Timing of Environmental Shifts on Cavitation Erosion during Two-Stage Tests

Abstract

Using a cavitating liquid jet apparatus, the authors conducted two-stage cavitation erosion tests with carbon steel samples (S15C) in seawater and tap water. The results obtained from the tests are as follows: (1) Even when the timing of a shift from the first stage environment (seawater) to the second stage environment (tap water) was changed, and in the reverse case or the environment was changed multiple times, the mass loss of sample metals by cavitation erosion after deceleration was smaller than the figure measured in the seawater environment. (2) In this case, the relative erosion resistance of the shift tests during the incubation period was slightly higher than that of the tap water environment, and the resistance of the shift tests during the acceleration period was almost equal. (3) The relative erosion resistance depended on the ratio of the total exposure time in the first stage environment to the total exposure time, even when the timing of an environmental shift was changed, or the environment was changed multiple times between the first and second stages.