【作者】 陈勇；

【导师】 郭斌；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2008， 硕士

【摘要】 现代旋压技术是广泛应用于航空、航天、军工等金属精密加工技术领域的一种先进塑性成形工艺。强力旋压作为旋压技术的一个重要组成部分,它在制造精度高、长径比大的薄壁筒形零件加工中,显出了独特的优越性,己成为成形小批量、多品种回转型薄壁壳体零件的重要加工方法。由于筒形件强旋影响因素众多,目前中高强度钛合金大型薄壁筒形件强旋技术还存在很多不足。为了系统地研究强力旋压的成形规律,本文采用有限元数值模拟和试验相结合的方法研究薄壁钛合金筒形件强力旋压。通过对强力旋压过程的分析,有效地处理了旋轮加载和边界约束等条件,对坯料和芯模、旋轮进行了模型的离散化,建立了符合实际的三维有限元模型。本文使用ABAQUS/Explicit对BT20钛合金强力旋压过程进行了模拟,得到了强力旋压过程中的应力场和应变场分布。结果表明,旋压不同阶段、不同部位坯料的应力应变状态和变形方式不同。旋轮作用区是典型的三向压应力状态;除旋轮作用区外,其余区域沿环向均受拉应力;在轴向上已变形区和未变形区都受到压应力作用。分析了强旋变形时金属变形流动规律,揭示了强旋的变形特点,为后面组织性能分析打下基础。通过对钛合金不同坯料状态进行组织观察和性能测试为强旋旋试验提供了依据。在旋压试验过程中,分析了旋压工艺对成形零件质量的影响。本文也对BT20钛合金筒形件热强旋组织进行了分析,得到了旋压组织的演变规律。观察了不同道次坯料的金相组织,发现了坯料内外层组织的差别,得出了坯料流动规律。观察了不同道次内外层坯料织构,得到了旋压织构演变规律。进行旋压筒形件的力学性能实验,得到了坯料内层和外层沿轴向和切向的拉伸强度和延伸率的差别,得到了坯料组织和织构影响坯料性能的规律。更多还原

【Abstract】 Modem spinning technology is an advanced plastic forming process and widely used in the field of precise processing technology of aerospace and military industry. Power spinning,one important part of spinning,has unique advantage when the thin wall tube of high precision,large slenderness ratio is made. It is became an important shaping method for flexible manufacturing of small-lot rotary thin-wall parts. At present, power spinning technology of cylindrical workpiece of titanium alloys with middle and high strength has many problems because power spinning is influenced by many factors which are difficult to be quantified and controlled. The way of combining FEM numerical simulation and experiment is adopted to research spinning process of thin-walled cylindrical workpiece of titanium alloys in this thesis.Based on analysis of the power spinning process,the boundary condition and the determination of load type are disposed effectively. The solid and shell element is used in discretion the blank and mandrel,roller respectively. The mechanical model,which fit well with the real process of tube spinning,is established.In this paper, ABAQUS/Explicit is used for analyzing the process of power spinning. The stress-strain status of different areas in raw material during different step and cause of drawback occurring are analyzed. During the forming Process,atypical three-dimensional compression stress zone lies in the place contacting with rollers. The hoop tension stress lies in other zones. The normal compressive stress lies in the formed place and unformed place. The distribution of stress field and strain field is given and the law of deformation and flow of metal is studied. The feature of power spinning is described. These results may be related to organization and property.It provides the basis for the conventional spinning experiment through the texture observation and performance testing of the different stock conditions of the Titanium alloy. In the process of spinning experiment, it has analyzed the influence of spinning technological parameter on the end parts quality, and brought in the scheme of controlling spinning technological parameter. Microstructure of hot power spinning of BT20 titanium alloy has also been analyzed, and distributions of spinning microstructure are obtained.更多还原