This work focuses on the relation between the sphericity and compactness parameters obtained from the exhaustive analysis on the graphite nodules of a spheroidal graphite cast iron sample, in order to propose a methodology with allow establishing different quality categories of nodules. The experimental methodology involves X-ray micro-computed tomography on an ad hoc test sample to generate high-resolution 3D images and the processing/postprocessing of the resulting 3D images through several image analysis routines. Based on the evaluations of sphericity and compactness distributions of 9238 nodules, different quality categories, called subpopulations, are proposed. In addition, a threshold value for the sphericity parameter of the graphite nodules, which allows characterizing the graphite nodules of the highest quality, is identified. The results provide new insights for better understanding of the geometric characterization of graphite nodules and its distribution on spheroidal graphite cast iron by using the sphericity and compactness parameters. The methodology proposed is identified as a powerful tool to analyze, in a non-destructive way, not only the quality of spheroidal graphite cast iron parts with different size and geometry, but also other materials.

中文翻译：

---

使用 X 射线显微计算机断层扫描和图像处理研究球状石墨铁的球度和致密度参数

这项工作的重点是通过对球墨铸铁样品的石墨球进行详尽分析获得的球度和致密性参数之间的关系，以提出一种允许建立不同质量类别的球墨的方法。实验方法涉及对临时测试样本进行 X 射线显微计算机断层扫描，以生成高分辨率 3D 图像，并通过多个图像分析程序对生成的 3D 图像进行处理/后处理。根据对 9238 个结核的球形度和紧密度分布的评估，提出了不同的质量类别，称为亚群。此外，确定了石墨球度参数的阈值，该阈值允许表征最高质量的石墨球。该结果为更好地理解石墨球的几何特征及其在球墨铸铁上的分布提供了新的见解。所提出的方法被认为是一种强大的工具，不仅可以以非破坏性的方式分析具有不同尺寸和几何形状的球墨铸铁零件的质量，还可以分析其他材料的质量。