立式离心场下钛合金熔体充填及凝固过程研究

研究立式离心场下不同铸造工艺参数对钛合金熔体的充填及凝固缺陷形成的影响。结果显示,立式离心场下得到的钛合金铸件质量优于重力场下的铸件。立式离心场下,合金熔体由于受离心力和科氏力的作用,沿着与旋转方向相对的型壁进行充填,且熔体的截面面积随充填长度的增加而逐渐减小,但是在内浇口处由于速度降低导致截面面积有所回升。此外,铸型的旋转方向,旋转半径及旋转速度直接影响铸件缺陷的形成。旋转方向直接影响合金熔体的充填顺序,进而影响合金熔体的凝固顺序及缺陷位置。实验结果显示,旋转半径及旋转速度的增加有利于减少铸件的缺陷体积。

Research on Mould Filling and Solidification of Titanium Alloy in Vertical Centrifugal Casting

The objective of this paper is to study the filling process of titanium alloy melt in vertical centrifugal casting, as well as the effect of processing parameters on the formation of defects of titanium alloy castings. Experimental results show that the castings obtained in the centrifugal field are better than that obtained in the gravity field. The molten metal sticks to one side of the mould which is opposite to the rotational direction to fill in the vertical centrifugal field. And the cross-sectional area of the molten metal in the runner decreases with increasing of filling length, but has a back-up trend at the inlet of ingate due to the decreases of filling velocity at the ingate. The processing parameters such as rotational direction, rotational radius and rotational velocity play an important role in the formation of defects of titanium alloy castings. Different rotational direction leads to different filling sequence of molten metal, which then affect the following solidification and the formation of the defects. Under the given rotational velocity, the volume of inner defects of castings decreases with increasing of rotational radius and rotational velocity.