CORROSION OF AIRCRAFT LANDING GEAR STEELS

Carrier-based aircraft landing gear demands a tough, corrosion-resistant material. Because of its high tensile strength, 300M steel was accepted as the standard material for aircraft landing gear. However, its corrosion resistance and fracture toughness are low, and is ill-suited for advanced aircraft landing gear. A newly developed nickel-cobalt alloy steel, named ''AerMet 100,'' has an outstanding combination of high fracture toughness and high tensile strength. Since its mechanical properties surpass those of the 300M steel, it has great potential for application to aircraft landing gear and other fracture critical components. However, its corrosion behavior was not fully understood. This study was initiated to characterize the corrosion behavior. The characterization effort included clarification of stress corrosion cracking, immersion corrosion, salt spray corrosion, and humidity corrosion of AerMet 100 steel. For comparison, an identical study was concurrently performed for 300M steel. The results indicate that AerMet 100 steel is superior to 300M steel with respect to corrosion resistance as well as mechanical properties.