Investigation of failure analysis and failure delay strategy for H13 steel contact wire clip die

The H13 steel hot forging die for the contact wire clip experienced frequent premature failure during service, including early cracking, thermal wear and collapse. In this study, the failure form and causes of the contact wire clip die were analyzed, and the material composition, hardness, and metallographic structure of the specimens were examined using a direct reading spectrometer, Rockwell hardness tester, optical microscope, and scanning electron microscope. Additionally, mechanical properties of the materials were assessed through tensile and impact tests. Combined with finite element simulation analysis, the failure causes of the contact wire clip die are thoroughly analyzed and discussed. The heat treatment tests were carried out to optimize the heat treatment process. The optimized heat treatment process is 1060 degrees C quenching, first tempering 560 degrees C, second tempering 560 degrees C. The strength of the die material was significantly improved, with the tensile strength increased by about 28 % and the yield strength increased by about 58 %. According to the different forging process parameters, the forging forming simulation analysis was carried out. The forging process parameters of the contact wire clip were optimized by BP neural network and NSGA2 genetic algorithm, and the optimized parameters were determined as follows: blank temperature 1210 degrees C, die temperature 246 degrees C, forging speed 160 mm & sdot;s-1, friction coefficient 0.5. With the optimized process, the maximum stress and temperature of the die were reduced by 19.6 % and 4.9 % respectively. The die failure can be effectively delayed by optimizing the heat treatment process of the die and the forging process parameters of the contact wire clip.