Abstract: In order to solve the stress corrosion problem of nonflared aviation pipe, the stress corrosion test was carried out on 1Cr18Ni9Ti non flared pipe in simulated service environment by self-developed stress corrosion device. The external bending stress was applied according to the specified installation tightening torque, and aviation hydraulic oil was injected into the pipe for stress corrosion test. At the end of the experiment, the macro corrosion pits appear on the surface of No. φ12 Y-2 pipe, and other nonflared pipes pass the examination without any damage and leakage. After grinding and polishing, SEM and metallographic structure were used to observe the non-free catheters producing corrosion pits. The results show that the cracks occur in the line sealing position formed by the pipe and the joint in the stress concentration area. The cracks go along the grain boundary and pass through multiple grains, and finally lead to cracking.