Fracture Reason Analysis of the Chain Wheel Brace of Bicycle

By means of chemical composition analysis,microstructure examination,macro-micro fracture examination and EDS analysis,the fracture reason of chain wheel brace of bicycle was analyzed. The result showed that because of the overheated,there were remelting eutectic on grain boundaries,which embrittled them,and cracks emerged when used,which lower the fatigue resistance of the material,and led to premature fatigue failure.