Experimental investigation on safety and reliability of ball-eye under bending load in electrical systems

In view of the frequent failure of the ball-eye (BE) in the transmission line, the force analysis of BE in extreme weather is carried out, and a set of bending fatigue test equipment was designed. It is the first time to carry out the fatigue test of BE treated by normalising, annealing and quenching and tempering process under bending loads of 2330, 3495 and 4560 N. Meanwhile, the bending fatigue life curve is plotted. From the macro and micro point of view, the characteristics and the content of the elements of the fracture, and the influence of the internal structure on the mechanical properties of three samples of different heat treatment processes are analysed. Conclusion indicates that the mechanical properties of the BE treated by normalising process are best, whose microstructure is fine and uniform ‘ferrite + pearlite’. Comparing the life of BE withstood tension load, it is revealed that bending load is the main reason to accelerate the failure of BE.