Failure of a Throttle-Arm Assembly Because of Thread-Root Cracks in the HAZ
A throttle arm of an aircraft engine fractured and caused loss of engine control. The broken part consisted of a 6.4-mm (1/4-in.) diam medium-carbon steel rod with a thread to fit a knurled brass nut that was inserted into the throttle knob. The threaded rod had been welded to the throttle-linkage bar by an assembly-weld deposit made on the rod adjacent to the threaded portion. The fracture surface exhibited a coarse-grain brittle texture with an initiating crack at a thread root. The throttle-arm failed by brittle fracture because of the presence of cracks at the thread roots that were...
Failure of a Throttle-Arm Assembly Because of Thread-Root Cracks in the HAZ, ASM Failure Analysis Case Histories: Air and Spacecraft, ASM International, 2019, https://doi.org/10.31399/asm.fach.aero.c0047541
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