Application Of Numerical Simulation Technology In Solid State Processing Of Metalic Materials

With the development computer science, finite element method and finite difference method, it is possible to set up a model to describe the physical processes of solid state material processing and heat treatment processes. Then, the temperature field, stress field and microstructure field of these physical processes can been calculated accurately using finite element method and finite difference method. If some experimental works were carried out to demonstrate the accuracy of modelling and simulation results, then these solid state material processing and heat treatment processes can been accurately simulated by computer. Then the virtual solid state material processing and heat treatment processes can been realized based on computer simulation. The relationship between the properties of materials and the technical parameters of solid state material processing and heat treatment processes can been set up by a large amount of computer numerical simulation works. These numerical simulation results are useful to optimize the technical parameters of solid state material processing and heat treatment. The main results of this doctoral dissertation are as follow:A thermo-elastic-plastic model was developed to simulate the laser forming process of shipbuilding steel plate. The temperature field, stress field and strain field of shipbuilding steel plate during laser forming process were calculated. The effects of steel plate width, steel plate thickness, laser power, laser scanning velocity on final bending angle were studied. To evaluate the accuracy of the simulation, laser forming experiments were performed. The temperature and bending angle of steel plate were measured. The simulation results of temperature and bending angle of steel plate are in good agreement with experimental results.An elastic-plastic model was set up to simulate oil pan forming process. The stress field, strain field and thickness distribution of the oil pans during forming process were calculated. The thickness distributions of the oil pans after forming process were measured. The calculated thickness distributions of the oil pans agree well with those of the measurements.A thermo-elastic-plastic model was developed to simulate the inertia friction welding process of GH4169 superalloy large size ring form workpiece. The transient temperature field, stress field, and strain field of GH4169 superalloy large size ring form workpiece during inertia friction welding process were calculated. The temperature and the axial shortering of GH4169 superalloy large size ring form workpiece during inertia friction welding process were measured. The calculated temperature and axial shortening are in good agreement with the experimental results.A thermo-elastic-plastic model of hot continuous rolling process of special steel wire and rod was set up. The temperature field, stress field and strain field of 304 stainless steel wire and rod during 18 passes hot continuous rolling process were calculated. The surface temperatures of 304 stainless steel wire and rod during 18 passes hot continuous rolling process was measured. The calculated surface temperature agree well with the measured result.A thermo-elastic-plastic model of laser transformation hardening process has been developed. The temperature field, stress field during laser transformation hardening process and the width and depth of laser transformation hardening zone were calculated. The width and depth of laser transformation hardening zone and residual stress distribution were measured experimentally. The calculated width and depth of laser transformation hardening zone and the residual stress distribution are in good agreement with the experimental results.A heat transfer and microstructure evolution model of quenching process of 35CrMo steel cylindrical large forging was proposed. The transient temperature field and microstructure field of 35CrMo cylindrical large forging in quenching process were calculated. The temperature of 35CrMo cylindrical large forging in quenching process and the microstructu...