Ti-3Al-2.5V钛合金精密铸造浇注系统优化研究

摘要

The mold filling and solidification process of Ti-3Al-2.5V titanium alloy with different pouring systems (top-bottom,spiral,radial and tree pouring systems) in gravity field and vertical centrifugal field were studied by numerical simulation,and the mechanical properties and shrinkage defects of the castings were tested by actual casting experiments.The results show that the fluctuation range of oxygen content in the top-bottom pouring system under gravity field is large,the different casting systems have little influence on the mechanical properties of the alloy,and the simulation results of the shrinkage defects are well consistent with the actual casting conditions.The defects such as scab,sweat,and shrinkage are easy to produce because of the metal liquid turbulence under the gravity field.By comparison,the number of defects in the centrifugal field is relatively less due to the centrifugal force.%利用数值模拟方法,研究了重力场和立式离心场下,不同浇注系统(顶-底、螺旋、径向和树形系统)Ti-3Al-2.5V钛合金铸件的充型和凝固过程及缩孔缺陷分布规律,并通过实际铸造实验,对铸件的机械性能及缩孔缺陷进行了检测.结果表明,重力场下的顶-底浇注系统氧含量波动范围大,不同浇注系统对合金力学性能影响不大,缩孔的模拟结果与实际铸造情况都吻合较好.相比而言,重力场下由于金属液的紊流更容易形成夹杂、钛豆、缩孔等缺陷,而离心场下由于离心力的作用,形成缩孔等缺陷的数量相对较少.