ZTC4钛合金铣削工艺及其结构件加工变形研究

发布时间：2018-10-24 19:55

【摘要】：为满足现代航空航天产品高强度、高耐热性和结构紧凑等要求,铸造钛合金整体结构件在此类产品上的应用越来越广泛。然而,此类零件在机加工过程中容易产生让刀现象,钛合金的难加工性会使刀具磨损加快,材料的去除使结构件应力重分布,这些因素都会导致结构件产生较大的加工变形。本文以ZTC4铸造钛合金整体结构件为研究对象,采用实验和有限元仿真相结合的方法,研究了退火及应力重分布、切削载荷、刀具磨损等因素对结构件加工变形的影响,并提出了变形控制策略。完成的主要工作如下:1.通过单因素实验研究了各切削参数对切削力、切削温度的影响规律,并建立了经验公式。利用正交试验研究了刀具磨损与切削速度、每齿进给量、切削宽度的关系,指出在研究参数范围内,每齿进给量对刀具后刀面磨损影响最为明显,建立了后刀面磨损量与切削用量和时间的经验公式。2.利用有限元仿真和实验相结合的方法,研究了圆盘零件的退火热处理过程,建立了ZTC4钛合金退火热处理的有限元仿真模型。基于该模型,研究了结构件的退火热处理过程并建立了其初始应力场。3.基于有限元仿真,分别研究了退火及应力释放、切削载荷、刀具磨损对加工变形的影响规律,并耦合上述因素获得了结构件变形的预测值;利用三坐标测量机测量实际加工结构件最终变形量,对比仿真结果,验证了有限元模型的准确性。利用遗传算法进行了加工参数的优化,提出了刀具补偿的方法来减小加工变形,通过有限元仿真,验证了优化后的参数和补偿后的路径确实能控制变形。
[Abstract]:In order to meet the requirements of modern aerospace products such as high strength, high heat resistance and compact structure, cast titanium alloy integral structural parts are more and more widely used in this kind of products. However, this kind of part is easy to produce the phenomenon of turning tool in the process of machining, the difficult machinability of titanium alloy will speed up the wear of the tool, and the removal of material will cause the stress distribution of the structural part to redistribute, all these factors will lead to the larger machining deformation of the structural part. In this paper, the effects of annealing and stress redistribution, cutting load and tool wear on the machining deformation of ZTC4 cast titanium alloy monolithic structure are studied by means of the combination of experiment and finite element simulation. The deformation control strategy is also proposed. The main work accomplished is as follows: 1. The influence of cutting parameters on cutting force and cutting temperature was studied by single factor experiment, and the empirical formula was established. The relationship between tool wear and cutting speed, feed per tooth and cutting width is studied by orthogonal test. It is pointed out that the influence of feed per tooth on tool surface wear is the most obvious in the range of research parameters. An empirical formula for the amount of wear on the rear tool surface and the cutting parameters and time is established. 2. The annealing heat treatment process of disk parts was studied by means of finite element simulation and experiment, and the finite element simulation model of ZTC4 titanium alloy annealing heat treatment was established. Based on this model, the annealing heat treatment process of structural parts is studied and the initial stress field is established. Based on finite element simulation, the effects of annealing and stress release, cutting load and tool wear on machining deformation are studied, and the predicted deformation values of structural parts are obtained by coupling the above factors. The accuracy of the finite element model is verified by measuring the final deformation of the actual machined structural parts by using the CMM and comparing the simulation results with the simulation results. The genetic algorithm is used to optimize the machining parameters, and a tool compensation method is proposed to reduce the machining deformation. The finite element simulation shows that the optimized parameters and the compensated path can control the deformation.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V261.23

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