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 晶粒的几何特征度量是金属性能分析的重要基础。文章对钢金相图像中晶粒的晶粒度、面积、直径、均匀度和晶界的光滑度等进行了定义，指出用晶粒的平均面积或平均直径来表征晶粒度或晶粒尺寸，用面积和直径与它们各自的平均值的偏差程度来估算晶粒的均匀度，用晶界跟踪的方向数来估算晶界的光滑度，最后给出了它们相应的估算公式。文章描述的晶粒几何特征度量方法为金属显微图像的更深入分析，如对金属晶粒度的评级、机械性质的分析等提供了很大的帮助。

Geometrical Characteristics Analysis of Grain Microstructure in Steel

The geometrical characteristics analysis of grain is the important base of metallographical analysis.Firstly,the definitions of grain size,area,diameter,uniformity and smoothness are given in this article.The following are indicated: 1.Grain size is estimated by the grain average area or average diameter;2.Grain uniformity is estmated by the deviation of the grains size from their average value;3.Grain smoothness is estimated by the tracking orientation number of grain boundary.Finally,the corresponding estimative equations are given.The measurement methods of grain's geometrical characteristics in steel are very helpful for deeper analysis such as the grain level evaluation,mechanical property and so on.