Prediction Of Microstructure And Performance Distribution Of Heat-treated Parts And Structure Design By Computer Simulation Technique

Heat treatment occupies very important position to improve the potential of material property and meet the requirement of parts performance. The problem of accurate prediction of performance distribution parts after heat treatment has not been soluted by computer simulation technique for a long time. Meanwhile, it is extremely difficult to measure the stress distribution and variation in parts during the quenching process, which leads to some difficulties of the structure design of quenching parts.Based on the computer numerical simulation technology, the distribution of microstructure and hardness in parts after heat treatment is predicted and then is verified by experiment. The structure of quenching parts is optimizational designed according to the prediction results of stress distribution simulation in quenching process.First of all, the fundamental principles of finite element in heat treatment process such as heat transfer, phase change, stress and so on were discussed and analyzed. And then, a computer numerical simulation prediction system is obtained, which can predict the performance and microstructure in different location of the heat-treated parts. In the process of simulation, appropriate thermo physical parameters and coefficient of heat transfer should be chosen reasonably. Furthermore, the temperature field of parts after customary heat treatment including water quenching, oil quenching, normalizing, annealing and induction hardening is simulated and the the cooling rate of different location in parts were so obtained. Combined with the Maynier mathematical model, the microstructure and its content, hardness, thermal stress and their distribution of parts after heat treatment were accurately predicted. Moreover, the simulation results were verified by experiment, which clearly indicated the high reliability of this computer simulation method.Because of the difficulty for measuring the stress distribution and variation in parts during the quenching process, a temperature-stress-structure simulation model is established based on the temperature field simulation reliability by ANSYS program. The temperature coupling stress field are calculated, which includes the rules of coupling relation among temperature, stress and microstructure in parts during the quenching process. The prediction of maximum stress distribution and its variation lays the foundation for the structure optimizational design of quenching parts. Meanwhile, this model has an important referential meaning in forecasting and preventing the defects such as deformation, cracking in quenching process. The reamer structure is designed by this method.