Abstract: Analyzing nodularity, sphericity and dispersivity, a fuzzy evaluation model for the nodulizing grade of nodular cast iron is firstly set up by means of fuzzy mathematics. In order to modify and verify the model, many microstructure of all kind nodulizing grade of China state standard (GB9441—1988) are analyzed and summarized by the system of image analysis of the microstructure of nodular cast iron. Finally, a scientific and overall fuzzy evaluation model for the nodulizing grade of nodular cast iron is acquired. The method can be used to evaluate microstructure of other materials, and the result showed that the system has an important effect for pushing on quantitative metallography.

Key words: Fuzzy mathematics, Nodular cast iron, Nodulizing grade