【作者】 孙剑亭；

【导师】 杜凤山；

【作者基本信息】 燕山大学 ， 机械设计及理论， 2008， 硕士

【摘要】 淬火过程的计算机模拟是当今淬火过程研究和淬火工艺设计中必不可少的重要研究方法。因淬火过程影响因素众多,边界条件复杂,一直是淬火过程计算机模拟的薄弱环节。因此对其研究具有重要的理论和实际意义。对大型锻件淬火过程的计算机模拟,更是对提高工件性能、减少变形和开裂,控制和保证质量具有重要的意义。本文研究并设计了平板奥氏体不锈钢探头,运用多功能可控热处理实验设备进行了空冷、喷气、喷雾、水淬、油淬等五种冷却工况下冷却曲线的实测,根据反传热法和非线性估算法对综合换热系数进行求解,从而解决了换热系数影响因素多,求解困难的难题。淬火过程是一个复杂耦合的高度非线性问题,本文充分考虑了淬火试件瞬态问题、相变潜热问题、变热物性参数问题、以及温度场、显微组织场和内应力场相互耦合问题,通过DEFORM有限元软件建立了淬火过程的有限元计算模型。并通过试验对模型进行了验证,证明模型的可靠性。根据该有限元模型模拟了轴类件五种冷却工况下的温度场分布,研究了三种典型冷却工况下的热处理应力场和残余应力场分布,分析了淬火试件组织场分布和淬透层深度,为进一步深入研究组织和淬透层深度预测打下了良好的基础。该数值模型对研究和分析大锻件任一时刻、任一位置的温度、组织和应力的变化情况和进一步分析大锻件的淬透层深度、预报产品的组织性能、残余应力的分布等方面有着重要的实践指导意义。并为大型锻件的热处理工艺的合理制定提供了有效的理论依据。为实现淬火过程的智能化打下基础。更多还原

【Abstract】 The computer simulation of quenching process is indispensably important research means for the present quenching process research and technological design. Because the quenching process influence factor is multitudinous, the boundary condition is complex, always is the weak link which the computer simulation of quenching process. Therefore, it has important theory and practical significance to its research. The quenching process computer simulation of large forgings has a very important significance for the work piece performance improving, the reduction of distorts and cracks, the quality controlling and guaranteeing.This paper studied and has designed the square shape austenite stainless steel probe head, and has carried on the air cooling, gas cooling, spray cooling, water quenching and oil quenching and so on five kind of operating mode cooling curve actual using the multi-purpose controllable heat treatment test installation. Carried on the solution to the surface heat transfer coefficient according to the counter-heat transfer law and the non-linear estimate law, Consequently, the problem is solved that the influence factors are complicated and the surface heat transfer coefficient is difficult to figure out.The quenching process is a complex coupling highly non-linear problem. This paper had considered fully the quenching test sample transient state question, changes the latent heat question, changes the hot natural parametric problem, as well as temperature field, microstructure field and the internal stress field mutual coupling question. The FEM model of quenching process is built based on the FEM(Finite Element Method)software DEFORM. And has carried on the confirmation through the experiment to the model, Proved the model is reliable.According to the finite element model to simulate five cooling conditions of temperature distribution of shaft, and study of three typical cooling heat treatment conditions and residual stress field distribution, analysis of the quenching specimen microstructure distribution and harden depth, for further in-depth research microstructure and harden depth forecasts laid a good foundation.This numerical model to studies with analysis large forgings any time, any position temperature, the microstructure and the stress change situation and further analyzes the large forgings harden level depth, forecast product microstructure performance, residual stress distribution and so on aspects has a important practice instruction significance. Also it has provided an effective theory basis for the large-scale forging heat treatment craft reasonable formulation. It will build the foundation for realizing the quenching process intellectualization.更多还原