Characterization of Relieved Non-metallic Inclusions in Stainless Steel by Image Processing of Micrographs

摘要

In the previous work, a new method to identify the shape of an inclusion was developed with the aid of image processing equipment. An attempt has been made to characterize inclusions in stainless steel using the method. Classifying areas for circles, triangles, squares, bars and intricates has been determined more accurately on two dimensional chart of Y=L~2/(4Aπ) and x=πD~2/(4A). The inclusions were relieved on the surface of specimen by electrolytic etching with the SPEED technique. By these improvements, the inclusions with triangular, square, bar and intricate shape, as well as circular inclusions, were clearly classified. However, it seemed difficult to identify the chemical species of inclusion from its shape in the case of specimen from molten steel and CC slab. In the case of rolled sheet, the inclusions with different shape could be identified respectively. Therefore, the image processing of inclusions coupled with relieving of them by electrolytic etching might be one of the hopeful ways to characterize the inclusions in rolled sheet of stainless steel.