The material deformation, physical field distribution and die elastic deformation of final forging process are analyzed. The shape and size of preform are optimized by response surface method and numerical simulation. The forming load and maximum equivalent stress are taken as the objective function, The regression model is established and the fitting is verified. The forging process, the elastic deformation of die tooth profile and the shape scheme of blank section are analyzed, which provides a reference basis for the design of final forging process from many angles. The details are as follows:
(1) The finite element numerical simulation of the final forging process is carried out, and the forming law of gear filling is obtained: with the downward movement of the die, the material first forms the large end tooth root of the tooth shape and gradually fills the cavity, and finally forms the small end tooth top of the tooth shape. After the cavity is filled, the excess material flows to the flash. The values of equivalent stress and strain distributed at the tooth root are large, and the maximum forming load in the whole final forging process is about 7.69x10000kn. After forming, the tooth shape of the forging shall be fully filled and the flash shall be uniform.
(2) In the forging process, uneven elastic deformation occurs on the die tooth profile, the tooth profile height decreases and the midpoint helix angle decreases. From the big end to the small end of the tooth profile, the deformation on the inner and outer tooth surfaces decreases gradually. For the same section, the displacement of the tooth surface on the outside of the helix is greater than that on the inside, and the shape of the tooth profile becomes narrower. It is proposed that the tooth profile should be corrected according to the inverse compensation method in the process of die design, so as to reduce the error caused by the elastic deformation of die tooth profile.
(3) The shape and geometric parameters of the preform are optimized by using the response surface method and numerical simulation. The two fillet radii on the blank section are shown in the sum, the platform length Z and the cone angle (x is taken as the design variable, and the equivalent stress and forming load are taken as the objective function to establish the regression model. The optimal parameter combination is R1 = 10.40mm, R2 = 15.60mm, l = 19.50mm, α= At 16.80 °, the optimal equivalent force is 156mpa and the load is 45853kn, which is 50.9% and 40.4% lower than that before optimization.