基于ObjectARX技术的铸件凝固进程数值模拟和凝固条件对凝固组织的影响

【作者】 马鑫；

【导师】 郑贤淑；

【作者基本信息】 大连理工大学 ， 材料加工工程， 2004， 硕士

【摘要】 采用铸造工艺凝固进程数值模拟的方法，进行铸造工艺的优化设计，是现代热加工过程通常采用的方法。而铸造凝固进程数值模拟的目的是为了通过数值计算，在计算机上动态的显示铸件的凝固过程，从而分析凝固过程可能产生缺陷的原因，并在此基础上优化铸造工艺，改变铸件的凝固条件，从而获得优质的铸件。可见，铸件在不同的凝固条件下凝固，具有不同的凝固组织。因此，研究凝固条件对凝固组织的影响，对于优化铸造工艺、获得优质铸件具有重要意义。而凝固进程数值模拟则是分析的基础。 本文使用AutoCAD二次开发—ObjectARX技术编制的铸件凝固进程数值模拟程序，在AutoCAD环境下集工艺设计和模拟计算于一体，并且对实体进行表面网格细化，增强了视觉效果。此程序作为AutoCAD的动态链接库，在AutoCAD环境下加载和运行，不仅其界面具有AutoCAD风格，容易被接受；而且集工艺设计和模拟计算于一体，避免了AutoCAD和其他计算软件的切换，提高工作效率；还可直接调用AutoCAD的功能，减少编程工作量。 在铜型、45钢型、石墨型、铬钢型和砂型五种铸型条件下制作4.5％的Al-Cu合金试样，得到不同的凝固组织。并在温度场数值模拟的基础上，分析凝固条件中温度梯度对凝固组织的影响。结果发现，在45钢型、石墨型、铬钢型铸型条件下制备的试样，在凝固组织中存在CET(Columnar to Equiaxed Transition，柱状晶向等轴晶转变)转变，在CET位置处，在固相率为0.4-0.8范围内，温度梯度随固相率呈线性变化，而且温度梯度对固相率的斜率与CET位置成线性关系，并且可以根据此关系预测铸件凝固组织中CET转变位置。更多还原

【Abstract】 Adopt the way of numerical simulation in the solidifying process of casting craft to optimize the casting craft, it is a broadly used method in the course of modern hot procedure. The purpose of numerical simulation of solidification process is to analyze the causations of disfigurements produced in solidification process showing the dynamic process though numerical simulation. On the basis of it, high quality castings can be acquired using the method of optimizing the casting craft and changing the solidification condition. So it is obvious that castings have different solidification structures under different solidification conditions. Thus, it is very significative to study the influence of solidification conditions to solidification structures. Moreover, numerical simulation of solidification process is the basis of analyse.Numerical simulation of solidification process programmed in the second exploiture technique-- the ObjectARX technique in the papers, collects technics design and numerical simulation together under the environment of AutoCAD, and strengthens the visual effect fractionazing the surfaces of entity. Used as a dynamic link library of AutoCAD and loaded and run under the environment of AutoCAD, the program not only shares the AutoCAD style thus it is easy to be accepted, but also collects technics design and numerical simulation together so switch is avoided between CAD and numeration. Nay, the program effectively decreases the quantity of writing software using the functions of AutoCAD directly.Using the method of numerical simulation joint with experiments, the influence for temperature gradient to Solidification Structure under the different solidification conditions was investigated. The results show that the relationship between the temperature gradient and the solid fraction is linear when the solid fraction is among the range of 0.4-0.8. further, the relationship between slope of temperature gradient and CET position is liner .On the basis of it, the CET position can be forecast.更多还原