工具阴极反拷法及其在Ti-Al叶片电解加工中的应用

发布时间：2018-05-14 11:32

本文选题：电解加工 + 钛铝叶片　；参考：《南京航空航天大学》2017年硕士论文

【摘要】：TiAl材料因其自身轻质和耐高温等优异性能,逐渐广泛应用到航空发动机叶片中,然而该材料室温塑性低、硬度高,机械加工非常困难。电解加工是一种基于阳极溶解的加工方式,非常适合加工TiAl叶片。但是电解成型规律复杂,精确设计阴极非常困难,反复修正阴极也往往延长叶片电解加工准备周期。反拷法通过标准叶片反向拷贝制备工具,再用制备的工具加工工件,是一种快速获得工具电极的工艺方法。然而电解加工并非可逆过程,且反拷加工过程涉及两次电解加工误差,其工件成型精度难以满足航空发动机叶片制造要求。本文以发动机TiAl叶片为研究对象,以提高反拷法加工精度为目标,展开了叶片型面和进排气边的反拷法实验加工,本文主要研究内容如下:(1)提出了叶片“变参数等小间隙”反拷法。在分析反拷法误差构成的基础上,通过反拷前后的电场、流场及阳极动态成型有限元仿真分析,明晰了加工间隙大小以及两次电解加工过程间隙的一致性是影响反拷法加工精度的核心要素,形成了变参数等小间隙反拷法加工方案。(2)开展了叶片型面“变参数等小间隙”反拷法电解加工试验。首先展开1Cr18Ni9Ti叶片型面的反拷法加工试验,试验结果均表明减小加工间隙和提升两次电解加工一致性将有助于电解加工精度的提升,证明了“变参数等小间隙”反拷法的有效性。在上述研究基础上,采用“变参数等小间隙法”开展TiAl叶片的反拷法加工,试验结果表明反拷后的TiAl叶片型面轮廓精度达到0.071mm,验证了“变参数等小间隙法”在TiAl叶片加工中的可行性。(3)提出了基于端面进给的进排气边反拷法电解加工方法。依据真实叶片进排气边轮廓,开展了1Cr18Ni9Ti材料的进排气边反拷法加工基础试验,成功加工出柱状进排气边曲面试件,试件轮廓精度达到0.062mm,实验结果证明了端面进给进排气边反拷法加工的可行性。
[Abstract]:TiAl material has been widely used in aero-engine blades because of its light weight and high temperature resistance. However, the material has low room temperature plasticity and high hardness, so it is very difficult to machining. Electrolytic machining is a kind of anodic dissolution based machining method, which is very suitable for machining TiAl blades. However, it is very difficult to design the cathode accurately because of the complex law of electrolytic forming, and the preparation period of ECM is often prolonged by modifying the cathode repeatedly. Reverse torture is a rapid method to obtain tool electrode by reverse copy of standard blade and then use the tool to process the workpiece. However, ECM is not a reversible process, and the reverse machining process involves two ECM errors, and the forming accuracy of the workpiece is difficult to meet the requirements of aero-engine blade manufacturing. In this paper, the TiAl blade of engine is taken as the research object, with the aim of improving the precision of the reverse torture machining, the experimental processing of the blade profile and the inlet and exhaust edges is carried out. The main contents of this paper are as follows: (1) the method of "variable parameter equal small gap" is put forward. Based on the analysis of the error structure of the reverse torture method, the finite element simulation analysis of the electric field, flow field and anode dynamic forming before and after reverse cuffing is carried out. It is clear that the size of machining clearance and the consistency of gap between two electrolytic machining processes are the core factors that affect the precision of reverse torture machining. The experiment of "variable parameter equal small gap" reverse torture machining was carried out on the blade surface. The experimental results show that reducing the machining gap and raising the consistency of two ECM will help to improve the precision of ECM, and prove the effectiveness of "variable parameter and small gap". On the basis of the above research, the "variable parameter equal small gap method" was used to carry out the reverse processing of TiAl blades. The experimental results show that the contour accuracy of TiAl blade profile is 0.071 mm, which verifies the feasibility of "variable parameter equal small gap method" in TiAl blade machining. According to the contour of the real blade inlet and exhaust edge, the basic experiment of the back grilling method of the inlet and exhaust edge of 1Cr18Ni9Ti material was carried out, and the cylindrical inlet and exhaust edge curved specimen was successfully processed. The contour precision of the specimen is 0.062 mm. The experimental results prove the feasibility of the end face inlet and exhaust edge reverse processing.
【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】：2017
【分类号】：TG662

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