In-Situ Observation of Behavior of Equiaxed Grains in Horizontal Centrifugal Casting Process
In-Situ Observation of Behavior of Equiaxed Grains in Horizontal Centrifugal Casting Process
复制标题
水平离心铸造过程中等轴晶行为的现场观察
DOI：
10.2355/tetsutohagane.97.369
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
K. Shinozuka
中科院分区：
文献类型：
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作者：
H. Esaka;J. Hiramoto;Shota Miyahara;Kei Tokusashi;K. Shinozuka
离心铸造技术已广泛应用于管材等长形产品的生产。在这种铸造中，有时会出现宏观偏析等问题。但是，我们还没有找到有效的对策。这可能是因为人们对离心力作用下的固结现象本身还没有很好的了解。因此，为了了解离心铸造中的凝固过程，利用新开发的实验装置，使用透明物质进行了原位观察。该设备的优点之一是在旋转轴上安装了摄像机，可以在整个固化期间观察预定区域。由于施加的热梯度，透明物质向内凝固。在初始阶段，柱状枝晶从边缘生长。然后，在液相中形成等轴晶。等轴晶不仅沿径向振荡，而且沿切向振荡，与旋转同步。这种振荡随时间的变化是由于表观粘度随固结的进行而增加。
Synopsis : Centrifugal casting technique has been widely used to produce long products, such as pipes. In this casting, sometimes problems such as macroscopic segregation arise. However, we have not found effective countermeasures. This reason may be attributed to the fact that solidification under being applied centrifugal force itself has not been well understood. Therefore, in order to understand the solidification process in centrifugal casting, in-situ observations using transparent substance have been performed by an experimental equipment newly developed. One of the advantageous points of this equipment is that a video camera is installed on the rotating shaft enabling observation of predeter-mined area during whole period of solidification. Owing to the thermal gradient imposed, transparent substance solidifies inward. At the initial stage, columnar dendrites grew from the rim. Then, equiaxed grains formed in the liquid phase. Equiaxed grains oscillated not only in radial direction but tangential direction synchronized with the rotation. This movement became smaller as solidification proceed-ed. This change in oscillation with time is due to the increase of apparent viscosity as solidification proceeds.