Study on corrosion resistance of aircraft conduit connector at simulated service environment

Corrosion resistance, airproof property and oil proof property of aircraft conduit connector of Cd-electroplated 45^# steel were studied by a conduit connector corrosion experiment system at simulated service environment. Cd-electroplated 45^# steel was placed in the solution of 6% NaCl at 90±5°C for 5 minutes and then in the air at 60±5°C for 25 minutes. This process was cycled for 200 times. The behaviors of surface corrosion and stress corrosion of the connectors were evaluated and the corrosion mechanism was investigated. It was not found that 45^# steel was corroded in No.10 fuel. Only slight corrosion was found on the surface of 45^#steel at simulated service environment. It was shown that the Cd-electroplated layer as anode plating layer on 45^#steel has excellent protection to the matrix metal. The result of the experiment under the bending stress of 0.85σ_s indicated that the Cd-coated 45^# steel has good corrosion resistance to SCC. Galvanic corrosion of LF2-M coupled with 45^# steel was investigated. It was found that the galvanic current of the couple of LF2-M coupled with 45^# steel is very low. The mean galvanic corrosion current is 0.185 μA/cm². It was demonstrated that the conduit of LF2-M and its connector of 45^# steel can be coupled safely.