| Abstract Scope |
Fatigue is the phenomenon leading to fracture under repeated or fluctuating stresses less than the tensile strength of the material. There are three stages of fatigue failure: initiation, propagation and final fracture. The present investigation was conducted on threaded bottom stud which connects the Push Rod that broke during the cyclic test. The breakage occurred near the root of the thread of the bottom stud, further observation of fracture surfaces reveals the presence of “beach marks” and “ratchet marks’’, cracks were initiated near the outer surface of the top stud. The failure analysis conducted to identify macro-scopic and micro-scopic features on the fracture surface through Stereo-microscopy and SEM respectively, while contaminants were identified through EDAX system. Metallography was conducted to know any material anomalies in metallurgical microstructure. The root cause of the failure was concluded as; the fatigue resulted through the repetitive loading and the evidence of Fluorine contaminants |