The service life of spiral bevel gear blank hot forging die plays an important role in the process of hot forging production. The wear of spiral bevel gear blank hot forging die affects the service life of the die. In the process of hot forging, the hot forging die of spiral bevel gear blank needs to bear high temperature, high working pressure, sudden change of temperature and high friction, and all these factors lead to the change of die geometry due to die wear or plastic deformation, the deterioration of surface finish of spiral bevel gear blank hot forging die, breaking the lubrication of die surface, causing die cracking or fracture, and even die failure. This wear failure not only affects the production cost, but also affects the forging tolerance. Wear is one of the main factors affecting the service life of the die. Therefore, it is important to study the wear behavior of spiral bevel gear blank hot forging die. Wear prediction is the most effective method to optimize the hot forging process.
Due to the diversity of hot forging die wear of spiral bevel gear blank, it can be divided into several types according to the wear mechanism, such as adhesive wear, abrasive wear, surface fatigue wear and so on. Adhesive wear is the main way of wear. This paper uses DEFORM-3D software to simulate and calculate the adhesive wear of spiral bevel gear blank hot forging die. Through the cumulative wear of single simulation and the maximum allowable range of spiral bevel gear blank hot forging die wear, the wear life of spiral bevel gear blank hot forging die can be roughly estimated. At the same time, the influence law of various forming factors on adhesive wear is studied through simulation, and then the process design to reduce wear and the design method of hot forging die for spiral bevel gear blank are found.
(1) Based on the modified wear model, the secondary development of DEFORM-3D is carried out, the process parameters of closed die forging process for the production of driven spiral bevel gear blank are designed, and the effect curves of each parameter on the forming load and the wear of upper and lower dies are obtained.
(2) The orthogonal design method is used to determine the test scheme. Taking the forming load and the die wear of the upper and lower dies as the optimization objectives, the optimized process parameters are as follows: die hardness 60HRC, forging speed 30mm / s, spiral bevel gear blank hot forging die preheating temperature 200 ℃ and blank initial temperature 1050 ℃. The optimized parameters are verified, and the life of spiral bevel gear blank hot forging die is predicted and compared with the actual die in the factory. The results show that the designed process parameters have a good reference value for actual production and die life prediction.
(3) Based on the study of the wear of spiral bevel gear blank hot forging die, the die stress is analyzed, and the influence curve of the tolerance value on the upper and lower die load and blank load is obtained. It can be found that when the tolerance value is between 1-10, the upper die load tends to be stable and the difference between the upper die load and blank load is very small. When the tolerance value is between 2-10, the lower die load tends to be stable and the difference between the lower die load and the blank load is very small.