The processing and fracture analysis on transmission shafts of a peanut harvester

In this study, the lifespan of the transmission shafts is discussed from the view of microstructure. The transmission shafts are made by the processes of hot rolling, machining, heat treatment and grinding. It shows a great difference of lifespan varied from 2 months to 12 months under the same using condition, with the three transmission shafts made by different hot rolling and heat treatment process. Metallographic examination, and micro-hardness measurement along transverse and longitudinal cross-sections of the shafts reveal the forming and heat treatment process of the three kinds of failed transmission shafts. Furthermore, fracture surface examination and mechanics analysis can be used to determine the fracture mode of failed transmission shafts. Scanning electron microscope can conduct the fracture surface examination of failed shafts, and the finite element analysis is used to analyze the stress distribution of transmission shafts. Based on this study, the facts of fracture mode of the transmission shaft, and the best hot rolling condition as well as the heat treatment condition to get the better lifespan can be found.