金属材料に生ずるキャビテーション損傷の指標

キャビテーション・エロージョン国際比較試験

抄録

Cavitation erosion tests were carried out on five metallic materials which are the standard materials of the International Cavitation Erosion Test Program which is co-ordinated by Dr. J. Steller. Three kinds of testing apparatus were used: a vibratory unit, a vibratory unit with a stationary specimen, and a water tunnel. The damage depth was chosen as the index of damage. This increased linearly against testing time after an incubation period during which no damage appeared. Damage depth vs. testing time lines under different intensity of cavitation attack were extrapolated back to the beginning of test to obtain a single characteristic point on the O-axis at which all these lines crossed the axis. By using Tabor's “the relation of one to one correspondence” between hardness and strain, the point was correlated to the amount of plastic strain which was accumulated within the incubation period. The slope of the line (damage rate) was related to the sum of occurrence frequency of cavitation impulsive pressure of which the intensity was larger than the tensile strength of the material.