Research Of The Stress And Strain Evolution On The Aluminum Alloy Hot Forging Die

Hot forging die plays a significant role in the rapidly developing industries such as automotive and mechanical industries. A large amount of hot work tool steel is consumed in China every year with the total price of hundreds of millions of RMB. Working under high temperature and pressure, hot forging die suffers from cyclic mechanical and thermal load, which causes the complicate distribution of its strain and stress both in time and in space. This complicate distribution results in low life cycle of the die. Recent years, more researches have been focused on the forging processes. However, the load condition of hot forging die itself has not been taken enough account into. So it is important to intensify the research on the load status of hot forging die. In order to better reflect the load condition of die during the forging process, a new simulation method for hot forging die load condition analysis based on the forming simulation result is proposed in this thesis. The main procedures for this method are as followings:First of all, simulate the forming process with forming analysis software Deform3D. During the simulation, the coupled thermal-mechanical method is used, and the forging part is taken as rigid-plastic body while the dies are taken as rigid bodies. When the simulation is completed, map the forming force of each increment from the part to the dies;Secondly, use the in-house developed software interface to extract nodal force and temperature data from Deform3D's Key file and write them into Marc's input file;At last, take the dies as elastic and deformable bodies, conduct structural analysis in Marc. The temperature, stress and strain distribution during the whole forging process will be obtained.The stress and strain evolution history of aluminum alloy hot forging die during the pre-forging process is mainly discussed in this thesis, and comparison is conducted under different forming speed. From the comparison, conclusion can be drawn: the higher the forming speed is, the higher the die stress is. With the proposed methodology in this thesis, the exact temperature and force boundary conditions for the dies are added to the FEM model in Marc, and the stress and strain histories for each node during the whole forging process are demonstrated. Since Marc is a very powerful FEA analysis tool, it can sever as the platform for further researches on hot forging die, hence the proposed methodology can serve as the preconditions to analyze the abrasion, fatigue and other conditions of hot forging die. Besides, this die structural analysis method based on the forming simulation results not only saves simulation time but also has a very good simulation convergence, it provides a feasible way for other die stress and strain analysis. This method can effectively support die development and provide some guidelines for industrial practices.