実機におけるキャビテーション・エロージョンの損傷速度の推定法

抄録

One of the characteristic features of cavitation erosion involves the removal of metallic material, which occurs after an incubation period, during which no mass loss, but plastic deformation of the surface, occurs. The current methods for predicting the amount of erosion damage inflicted upon metallic material in a cavitatiog environment are based on the mass of the material which is lost. As a consequence, the erosion-resistance of a material cannot be determined until a measurable amount of mass loss has occurred. In this study, in order to estimate the damage rate during the mass loss period, the plastic deformation behavior in the incubation period as well as in the mass loss period was analyzed. The increment of the surface area was determined from material surface profile data, measured through a surface roughness meter, and proved to be a good index for quantitatively evaluating the development of surface plastic deformation. It increased with testing duration, reaching a constant value after the incubation period. The value was related to the size of particles, which were separated from the damage surface. The value of the surface increment at the end of incubation period was closely related to the maximum strain which the surface can bear. This value can be used for estimating the cavitation damage rate.