The Development Of Quantitative Metallography Analysis System Based On Fractal Theory

Computer-aided quantitative metallography technology has the advantages of fast process,accurate data and good reproducibility of test results compared with traditional artificial metallographic analysis.With the development of computer technology,the trend of computer-aided quantitative metallography analysis instead of traditional metallographic analysis is inevitable.This paper makes use of Matlab and Visual C++ to develop a set of quantitative metallography analysis system based on fractal theory by using digital image processing technology and fractal theory.The whole system adopts modular design.The paper primanly complete the development of image processing module and quantitative metallography analysis module.Among them,quantitative metallography analysis module includes four submodules:grain size rating,spheroidization rating of ductile iron, spheroidization rating of pearlite and pattern recognition of fracture surface image.The image processing module firstly reads image file,then processes image according to specific requirements of metallographic analysis,finally completes the work of saving image file.This module summarizes advantages and disadvantages of various calculation methods,chooses and improves calculation methods of image processing to adapt to requirement of metallography analysis.The quantitative metallography analysis module uses fractal theory to quantitative metallographic analysis.The paper studies quantitative relations between fractal dimension and levels of grain size, fluctuating extent of graphite particles contour,nodulizing grade of pearlite and types of fracture surface image theoretically.According to research results, this module makes use of the linear minimum distance classifier and fuzzy comprehensive judgment theory to complete microstructure rating and pattern recognition of fracture surface image.Finally, the system is put into example analysis.The results show that:each module runs well,reaches design goal, can realize predetermined work of image processing and metallographic analysis. This syetem can put into practiacal application.