A New Approach to Calculate the Velocity of Interdendritic Fluid Flow during Solidification Using Etched Surface Height of Actual Metal Ingot
A New Approach to Calculate the Velocity of Interdendritic Fluid Flow during Solidification Using Etched Surface Height of Actual Metal Ingot
复制标题
利用实际金属锭的蚀刻表面高度计算凝固过程中枝晶间流体流动速度的新方法
DOI：
10.3390/met11060927
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发表时间：
2021-06
期刊：
影响因子：
2.9
通讯作者：
Dong Hongbiao
中科院分区：
文献类型：
--
作者：
Hou Zibing;Peng Zhiqiang;Liu Qian;Guo Zhongao;Dong Hongbiao
宏观偏析是影响金属材料性能的主要缺陷之一，其主要原因是凝固过程中枝晶间的流体流动。然而，对于控制实际的比偏析，仍然难以有效地测量或模拟这种流动而不是纯流体流动，特别是在高等级材料的复杂铸造过程中。本文提出了一种利用边界层和标准差，利用统计学原理获得金属凝固过程中枝晶间流体流动速度大小和方向的新方法。以GCr15轴承钢连铸大方坯为例，说明计算得到的不同侧边和过热度下的速度值可以用工艺特点和凝固机制来解释。内曲线侧和低曲率区流速幅值和脉动较大。同时，发现二次臂间距的波动幅度与枝晶间流体流动的关系更为密切，但其大小主要取决于冷却速率。此外，根据计算得到的速度方向和大小，偏析面积比与枝晶间流动速度与长大速度的有效比值之间存在正相关关系，尤其是在等轴晶区，这与经典的宏观偏析形成理论相一致。上述结果以及与其他结果的比较表明了该方法的有效性，该方法可以通过剪裁测量长度和测量数目来获得二维或三维多尺度速度分布下枝晶间流体速度的大小和方向。
Macrosegregation remains one of main defects affecting metal materials properties, which is mainly caused by interdendritic fluid flow during solidifying. However, as for controlling actual specific segregation, it is still difficult to effectively measure or simulate this kind flow instead of pure fluid flow, especially in complex casting processes of high-grade materials. Herein, a new method for obtaining velocity magnitude and direction of interdendritic fluid flow during metal solidifying is proposed from boundary layer and standard deviation obtained by measuring etched surface heights of the actual ingot and using statistical principles. Taking continuous casting bloom of GCr15 bearing steel as an example, it is indicated that the calculated velocity magnitudes under different sides and superheats can be explained by process features and, hence, solidification mechanism. The velocity magnitude and fluctuation are higher on the inner curve side and under low superheat. Meanwhile, it is found that the fluctuation extent of secondary arm spacing is more relevant with interdendritic fluid flow, although its magnitude is mainly determined by the cooling rate. Moreover, on the basis of the calculated velocity directions and magnitudes, there is a positive correlation between segregation area ratio and the effective ratio between interdendritic flow velocity and growth velocity especially in the equiaxed grain zone, which corresponds with classic macrosegregation formation theory. The above findings and comparison with other results demonstrate the validity of the new approach, which can obtain the magnitude and the direction of interdendritic fluid velocity for two or three-dimensional multiscale velocity distribution by tailoring measuring length and numbers.
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DOI：
10.2355/tetsutohagane.98.405
发表时间：
2012
影响因子：
0.3
作者：
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发表时间：
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影响因子：
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作者：
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影响因子：
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