Surface effects and flow conditions in small volume melts with varying sulphur content
Surface effects and flow conditions in small volume melts with varying sulphur content
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不同硫含量的小体积熔体的表面效应和流动条件
DOI：
10.1002/srin.200100087
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
P. Scheller
中科院分区：
文献类型：
--
作者：
P. Scheller
采用1 mm厚的X5 CrNi 18 -9（AISI 304）不锈钢带，用TIG（钨极惰性气体）燃烧器部分重熔，研究了几立方毫米熔体中的表面效应和流动行为。在工业生产的材料中，S质量含量在20和100 ppm之间变化。硫的表面过量表明与Fe-S体系中的值相比没有实现表面饱和。具有高硫富集的层的厚度取决于S活性，并且在约260和460 nm之间变化，并且在距表面约1.2 μ m的距离处实现本体S含量。该层明显比扩散边界层薄，并且比流动边界层薄得多。快速凝固的液体池的形貌使得有可能，考虑到先前估计的表面张力的温度系数，解释熔体中关于S含量和温度梯度的流动行为。结果表明，在小体积熔体中，由表面张力梯度（马兰戈尼效应）引起的剪切力控制着流动条件。
The surface effects and flow behaviour in melts with a volume of a few cubic millimetres were investigated using 1 mm thick X5CrNi18-9 (AISI 304) stainless steel strips after partial remelting by a TIG (tungsten inert gas) burner. In the industrially produced material the S mass content was varied between 20 and 100 ppm. The surface excess of sulphur indicates that the surface saturation was not achieved compared to the values in the Fe-S system. The thickness of the layer with high sulphur enrichment depends on the S activity and varied between approximately 260 and 460 nm and achieves the bulk S content at a distance of approximately 1.2 pm from the surface. This layer is noticeably thinner than the diffusion boundary layer and considerably thinner than the flow boundary layer. The topography of the rapidly solidified liquid pool makes it possible, taking previously estimated temperature coefficients of surface tension into account, to explain the flow behaviour in the melt with regard to the S content and to the temperature gradients. The results obtained indicate that the shearing force caused by surface tension gradients (Marangoni effect) controls the flow conditions in small volume melts.