开闭口圆环渗碳淬火残余应力与变形分析

发布时间：2018-06-15 01:01

本文选题：渗碳淬火 + 耦合　；参考：《燕山大学》2015年硕士论文

【摘要】：渗碳淬火作为改变和提高材料性能的重要手段,在汽车、航空、及其他制造业领域有着广泛的应用。但淬火过程是一个复杂的多场耦合过程,传统热处理技术已经不能适应机械现代化的要求,应用计算机技术改造热处理已成为当务之急。本文针对开闭口圆环等常见工件的淬火应力与变形问题,基于大型有限元分析软件ANSYS,对渗碳开闭口圆环的淬火工艺进行仿真模拟,分析其温度场与应力场的分布规律和开口圆环工件淬火变形特点。基于传热学基本原理,热弹塑性理论,相变理论,采用有限元软件ANSYS,对渗碳开闭口圆环淬火冷却过程的温度场进行的数值模拟。根据模拟需要,将参数连续变化的渗碳层简化为阶梯变化,利用APDL语言编制了试件模型以及渗碳层模型,各种材料参数的输入的命令流文件,可方便模型和参数的修改,实现模拟渗碳淬火过程的参数化分析。考虑了马氏体相变潜热,并根据温度场的模拟结果对马氏体组织转变过程进行了预测。将温度场模拟结果作为预定义场,对渗碳开闭口圆环淬火过程中的应力场进行模拟,分析渗碳开闭口圆环在整个淬火过程中应力场的变化规律,以及最终残余应力的分布情况。并对残余应力场的分布特点进行了分析,为零件渗碳工艺的确定提供理论参考。对渗碳开口圆环淬火后的变形问题进行了分析,探究了引起变形的原因以及变形的种类,观察淬火过程中,在热应力和组织应力共同作用下产生的开口圆环淬火变形,通过对比模拟结果中各方向上变形量的数值,研究了不同淬火温度和不同冷却速度条件对淬火变形的影响。
[Abstract]:Carburizing quenching, as an important means to change and improve the properties of materials, is widely used in automobile, aviation, and other manufacturing fields. However, the quenching process is a complex multi-field coupling process, the traditional heat treatment technology can no longer meet the requirements of mechanical modernization, the application of computer technology to transform heat treatment has become an urgent task. Aiming at the problem of quenching stress and deformation of common workpiece such as open and close ring, this paper simulates the quenching process of carburized open and closed ring based on ANSYS, a large-scale finite element analysis software. The distribution law of temperature field and stress field and quenching deformation characteristics of open ring workpiece are analyzed. Based on the basic principles of heat transfer, thermoelastic-plastic theory and phase transformation theory, the numerical simulation of the temperature field in the cooling process of carburized open and closed ring quenching is carried out by using the finite element software ANSYS. According to the need of simulation, the Carburized layer with continuous variation of parameters is simplified as a step change. The sample model and Carburizing layer model are compiled by using APDL language, and the input command flow files of various material parameters can be easily modified. Parametric analysis of simulated Carburizing quenching process is realized. The latent heat of martensite transformation is considered and the microstructure transformation process of martensite is predicted according to the simulation results of temperature field. The simulation results of temperature field are taken as the predefined field to simulate the stress field during the quenching process of carburized open and closed ring. The variation law of stress field and the distribution of final residual stress in the whole quenching process of carburized open and closed ring are analyzed. The distribution characteristics of residual stress field are analyzed, which provides a theoretical reference for the determination of Carburizing process. In this paper, the deformation of carburized open ring after quenching is analyzed, the causes and types of deformation are explored, and the quenching deformation of open ring is observed under the joint action of thermal stress and microstructure stress during quenching. The effects of different quenching temperature and cooling rate on quenching deformation were studied by comparing the values of deformation in different directions in the simulation results.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG156.3

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