On the Role of Corrosion in Cavitation Damage

Abstract

The interacting influence of corrosion on cavitation damage was studied quantitatively using a magnetostrictive device. The relationship between the rate of weight Joss and the amplitude of oscillation for 1020 mild steel became modified as the NaCl concentration was increased. When 1100-F aluminum was used, this relationship was not affected. An attempt was made to estimate the contribution of electrochemical corrosion to total damage of four methods; namely, (a) static polarization measurements, (b) dynamic polarization measurements, (c) short-duration pulsing technique, and (d) long duration pulsing technique. The electrochemical corrosion rates thus estimated are very small compared to the total rate of damage. However, the rate of weight loss in 3 percent NaCl solution (in distilled water) for 1020 mild steel is about three times that in distilled water at a particular double amplitude and frequency (1.5 X 10 −3 in. and 15 kcs). It is concluded that this increase in the rate of damage is principally due to the deterioration in the mechanical properties of the material in a corrosive environment.