Studies of Cavitation Erosion

On the time dependence of the rate of erosion

Abstract

For the purpose of making clear the causes of the variation in erosion rate, an experimental study was carried out of the cavitation erosion of iron and steel in a water tunnel system. Both scanning electron microscopic and metallographic observations were made on the damaged surface of the specimens with special attention to the behavior of ferrite which is contained in all of the materials tested.
As a result, the following conclusions are obtained. (1) Each ferrite in iron and steel has its own cavitation damage process, not always according to mechanical properties of the material damaged. (2) The mechanism of cavitation damage on Armco-iron turns from ductile to brittle with the lapse of testing time. (3) Some convincing evidence has been obtained to indicate that a part of the variation in erosion rate is caused by the transition of the mechanism of cavitation damage. Additional study is, however, necessary before this may be accepted as fact.