The traversing ring gear bearing assembly holds the upper and lower carriage assemblies of the howitzer together. When the ring gear bearing fractured, the gun tube fell to the ground. The failure analysis included destructive testing of the original gear and four additional gears to properly determine the cause of the fracture. Some fasteners
holding the ring gear bearing assembly together failed due to hydrogen embrittlement but the cause of failure of the ring gear was stress corrosion cracking.
Keywords: Stress-corrosion cracking, water intrusion, weapons system, hydrogen embrittlement, galvanic corrosion.