Failure analysis of metal alloy propeller shafts

Failure analysis of metal alloys propeller shaft used in marine has been carried out. The shaft fractured at shoulder with evidence of torsional-bending fatigue. Chemical composition, micro-structural characterization, fractography, hardness measurements, and finite element simulation were used for the analysis. Fatigue crack has initiated at the shoulder. The geometry of the fillet also promoted the initiation crack because the fillet were erroneously designed. It was concluded that all these factors produced fatigue failure. It is recommended to first guarantee the chemical composition and microstructure of the material. Secondly, use x111-T5-K4 flux cored wire additions in welding repair process to extend service life and, finally, accomplish the geometric parameters recommended by the standard to avoid high stress concentration factors.