Use of Electron Fractography to Diagnose Cracking in an AISI 4340 Nose Landing Gear Cylinder
Examination of a cracked nose landing gear cylinder made of AISI 4340 Cr-Mo-Ni alloy steel proved that the part started to fail on the inside diam. When the nucleus of the stress-corrosion crack was studied in detail, iron oxide was found on the fracture surface. A 6500x micrograph revealed this area also displayed an intergranular texture. One of a group of small grinding cracks on the ID of the cylinder nucleated the failure. Other evidence indicated the cracks developed when the cylinder was ground during overhaul.
James A. Scott, Use of Electron Fractography to Diagnose Cracking in an AISI 4340 Nose Landing Gear Cylinder, ASM Failure Analysis Case Histories: Air and Spacecraft, ASM International, 2019, https://doi.org/10.31399/asm.fach.aero.c9001538
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