Mechanisms and prevention of cavitation erosion in 1Cr18Ni9Ti fluid pipes

This study investigates recurrent leakage failures that occurred at nearly identical locations in 1Cr18Ni9Ti stainless steel pipes from multiple aircraft. Surface analyses reveal characteristic damage features: an inner-surface ‘valley’ with honeycomb-like craters and facets, contrasting with a single outer-surface perforation. The failure process involves progressive pit initiation, followed by the nucleation and multidirectional growth of fatigue cracks. Cavitation erosion is identified as the primary failure mode, whereby cumulative bubble collapse progressively reduces wall thickness. Simulations using AMESim and oil–gas two-phase flow models demonstrate that a sudden pressure drop creates low-pressure regions and promotes gas accumulation on the inner side of the pipe bend. These findings are consistent with the observed failure location and mode. Optimized design modifications are proposed and validated to enhance cavitation resistance of the pipe and prevent such failures.