Study on Repair Technology for Aircraft Fuel Pump Motor Rotating Shaft Based on HVOF

Abstract

The motor rotating shaft of an aircraft centrifugal fuel pump is prone to mechanical damage after long-time friction with the dynamic seal， which would cause fuel to leak from the fuel pump nozzle and affect flight safety.In order to address the wear of the rotating shaft， an additive repair technology that involved spraying a WC carbide coating on its surface using HVOF was adopted.Three WC-12Co carbide coatings，each with different microstructures and mechanical properties， were prepared on the surface of 2Cr13 substrate by adjusting the kerosene flows in the HVOF process.The effect of kerosene flow on the porosity， microhardness， fracture toughness， adhesive strength and wear properties of the coatings was investigated.Results showed that with the oxygen flow kept constant，an increase in the kerosene flow rate led to increased particle temperature and velocity， reduced porosity of the coating， and enhanced fracture toughness and adhesive strength of the coating.The denser the coating， the greater the hardness of the coating， and the dense structure could reduce the peeling of WC particles during friction， resulting in good wear resistance of the coating.The optimum processing parameters for rotating shaft repair were determined from these tests.After a run-in test of 1 000 h，the repaired rotating shaft exhibited no significant wear or damage，with the size change being less than 0.01 mm，and the product performance was found to meet the technical requirements.

Keywords

• rotating shaft|oil leakage failure|hvof|wc-12co coating|additive repair