The quality of spheroidal graphite cast iron (SGI) castings is directly related to the morphology of graphite nodules. Therefore, accurate and comprehensive quantitative evaluation of microstructure is critical for industrial practices. The most influential morphological characteristics of the graphite phase in SGI can be divided into three categories: (1) shape and size of individual graphite nodules, (2) total volume of graphite phase and nodule number, and (3) spatial distribution. During the last decades, SGI structure analysis has progressed from visual observation of polished cross section and quantitative 2D techniques (metallography and automated SEM/EDX) to observation of the real 3D structure using micro-computed tomography (µCT) scanning. In this article, 2D and 3D morphological characteristics of graphite nodules were determined by µCT scanning and compared. 3D µCT provides accurate characterization of the real shape factor and diameter of graphite nodules. It was shown that large and small graphite nodules in inoculated SGI have the different modes of space distribution which could be linked to casting solidification.

中文翻译：

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SGI中石墨结节的Micro-CT定量评估

球墨铸铁（SGI）铸件的质量与石墨球的形貌直接相关。因此，对微观结构进行准确，全面的定量评估对于工业实践至关重要。SGI中最有影响力的石墨相形态特征可分为三类：（1）单个石墨结节的形状和大小；（2）石墨相的总体积和结节数；（3）空间分布。在过去的几十年中，SGI结构分析已从目视观察抛光的横截面和定量2D技术（金相学和自动SEM / EDX）发展为使用微计算机断层扫描（µCT）扫描观察真正的3D结构。在这篇文章中，通过µCT扫描确定并比较了石墨结节的2D和3D形态特征。3D µCT可准确表征石墨结核的实际形状因数和直径。结果表明，接种的SGI中的大，小石墨结核具有不同的空间分布模式，这可能与铸件凝固有关。