Material selection and production method of automobile gear forging blank:
(1) Using the chemical composition of 20MnCr5 steel as the main basis, complete the batching of automotive gear forging blanks based on the chemical composition, and use the induction hardening process to heat treat the test samples to achieve the melting of the test samples. By smelting, pouring, and cooling the automotive gear forging blanks using the electroslag remelting method, the dimensions of φ 200 mm × 700 mm 20MnCr5 steel rod blank;
(2) The closed die forging method is used to complete the forging and pressing of test samples, and operations such as blanking, heating, upsetting, pre forging, final forging, and punching and connecting the skin are carried out on a self-made mold to achieve the production of automotive gear forging blanks;
(3) Using a die forging system to process the finished automotive gear forging stock can improve the basic performance of the material. The system includes upper and lower molds, automotive gear forging stock, and burr grooves. During the forging process of automotive gear forging blanks, the initial forging temperature of the entire production process is 1150 ℃, the final forging temperature is controlled at 800 ℃, and the forging deformation amount is 8.6%. The heat treatment process for automotive gear forging blank test samples is shown in the table.
| Sample No | Heat treatment process | Annealing temperature ℃ | Holding time h | Cooling method |
| 1# | Conventional annealing | 800 | 2.5 | furnace cooling |
| 2# | Conventional annealing | 820 | 2.5 | furnace cooling |
| 3# | Conventional annealing | 840 | 2.5 | furnace cooling |
| 4# | Conventional annealing | 860 | 2.5 | furnace cooling |
| 5# | Conventional annealing | 880 | 2.5 | furnace cooling |
| 6# | Isothermal annealing | 860 650 | 1.0 1.5 | furnace cooling |