In view of the problems of large material waste and high cost caused by the traditional die design and process formulation based on experience and test in the hot forging of spiral bevel gear blank, a numerical simulation method is proposed to study the forging process of spiral bevel gear. Aiming at the problem that the single-step method can not reflect the influence of the residual stress after the processing of the previous process on the next process, a multi-step numerical simulation of the forging process of spiral bevel gear is proposed, that is, the multi-step analysis of the upsetting process and die forging process is carried out. The main work is as follows:
(1) The upsetting process and die forging process of spiral bevel gear are analyzed in multiple steps, the metal flow law of upsetting process and die forging process is obtained, and the equivalent stress-strain and temperature distribution of forgings during final forging are obtained. Three points are taken on the spiral bevel gear blank, and the curves of equivalent stress, strain and temperature with time are obtained. The stroke load curve of the total forging process of spiral bevel gear is obtained, that is, the forming load of different strokes in the forging process of spiral bevel gear. The results show that during the final forging of spiral bevel gear blank, the large stress, strain and high temperature occur at the steps of the outer side and flash and the steps of the inner side and concave thin layer, indicating that the metal flow is difficult at these two steps. The numerical simulation results are compared with the real forging to verify the correctness of the numerical simulation.
(2) According to the numerical simulation results, the die structure of die forging process is improved. The influence of the temperature and strain distribution of the bevel gear blank before and after forging on the forming effect of the final forging die is analyzed.
(3) The effects of different initial forging temperature and friction on the forming effect of spiral bevel gear were studied.
(4) The relationship between forging energy consumption and initial forging temperature of spiral bevel gear was studied.