【作者】 张立文；

【导师】 王富岗；

【作者基本信息】 大连理工大学 ， 材料学， 2004， 博士

【摘要】 随着计算机科学、有限元及有限差分方法的发展,可以建立适当的理论模型,描述材料固态加工及热处理的物理过程。然后,采用有限元及有限差分法对这些物理过程的温度场、应力场、应变场、微观组织场等进行精确的定量数值模拟计算。只要通过少量的实验验证理论模型及数值模拟计算的准确性,就可以利用计算机对大量的实际材料固态加工及热处理过程进行准确的数值模拟。这样就实现了基于计算机数值模拟的虚拟材料固态加工及热处理过程。通过大量的计算机数值模拟计算,可以建立材料固态加工及热处理工艺参数与材料固态加工及热处理后性能的定量关系。这些数值模拟计算结果可以用于优化材料固态加工及热处理工艺参数。论文主要包括以下内容: 建立了船用钢板激光弯曲成形过程的热弹塑性力学模型。对船用钢板激光弯曲成形过程的温度场、应力场及应变场进行了数值模拟。研究了板材厚度、板材宽度、激光功率和激光扫描速度对激光弯曲成形最终弯曲角度的影响。进行了钢板激光弯曲成形实验,实测了钢板的温度及弯曲角度。钢板的温度和弯曲角度的数值模拟结果与实验测量结果符合较好。 建立了发动机油底壳冲压成形过程的弹塑性力学模型。对发动机油底壳在冲压成形过程的应力、应变及厚度分布进行了数值模拟。实测了发动机油底壳冲压成形后的厚度分布。厚度分布的数值模拟结果与实验测量结果符合较好。 建立了GH4169高温合金大环形零件惯性摩擦焊过程的热弹塑性力学模型。对GH4169高温合金大环形零件惯性摩擦焊过程的温度场、应力场及应变场进行了数值模拟。对GH4169高温合金大环形零件惯性摩擦焊过程的温度及轴向缩短量进行了计算机实时测量。温度及轴向缩短量的数值模拟结果与实验测量结果符合较好。 建立了特殊钢棒线材热连轧过程的热弹塑性力学模型。对304不锈钢棒线材18道次热连轧过程的温度场、应力场及应变场进行了数值模拟。实测了304不锈钢棒线材18道次热连轧过程各道次的表面温度。表面温度的数值模拟结果与实验测量结果符合较好。 建立了激光相变硬化过程的热弹塑性力学模型。对激光相变硬化过程的温度场、应力场和激光相变硬化区的宽度及深度进行了数值模拟。实测了激光相变硬化区的宽度和深度及残余应力分布。激光相变硬化区的宽度和深度及残余应力分布的数值模拟结果与实验测量结果符合较好。 建立了35CrMo钢圆柱体大型锻件淬火冷却过程的传热学、相变模型。对35CrMo钢圆柱体大型锻件淬火冷却过程的温度场、组织场进行了数值模拟。实测了35CrMo钢圆柱体大型锻件淬火冷却过程的温度和淬火后的组织场。温度和淬火后组织场的数值模拟结果与实验测量结果符合较好。 建立了真空热处理过程的传热学模型。对GH4169高温合金零件真空热处理过程的温度场进行了数值模拟。预测了GH4169高温合金零件在真空炉中加热过程的滞后时间。实测了GH4169高温合金零件真空热处理过程温度随时间的变化。温度随时间变化的数值模拟结果与实验测量结果符合较好。更多还原

【Abstract】 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更多还原