Through the process test of two different pre heat treatments on the deformation law of the parts after final carburizing and quenching, and the analysis and Research on the deformation law, the following conclusions are drawn:
(1) The deformation of gear with isothermal annealing of gear blank after carburizing and quenching is obviously smaller than that of gear with ordinary normalizing of gear blank. Taking 9t one speed gear as an example, after isothermal annealing, the average change momentum of common normal line after carburizing and quenching is only 61.7% of that in normalized state, and the average change momentum of m value is only 26.8% of that in normalized state.
(2) Due to the batch production and high precision requirements of heavy truck gears, the pre heat treatment of gear blank should adopt isothermal annealing treatment, so as to make good organizational preparation for the final carburizing heat treatment and lay a good foundation for controlling the carburizing deformation of gears.