Coarse carbides evaluation research based on area histogram

Manual methods are used to perform the classification of coarse carbides in metallic material, so a quantitative standard is needed necessarily to achieve the automatic classification. In order to obtain the standard and further perform processing and analysis of carbide metallograph, area histogram which was used in image retrieval is first introduced to metallographic analysis field. Average area histogram (AAH) and prominent area histogram (PAH) of different levels carbide spectrum are computed, and then the relationship between AAH&PAH and the distribution of carbide is found. We make the high speed tool steel as the example to obtain the standard evaluation with area histogram. Because a large number of small carbides, which are called second carbides, on the calculation of AAH generated interference, the calculation result is not satisfactory so filter coefficients is advanced and used to remove the impact of small pieces of carbides on analysis results. Filter coefficients is further discussed by means of experiments results and AAH&PAH which are regarded as a quantitative standard of the automatic classification are calculated based on the best filter coefficient.