Recognition of surface defects of rolled steel in sheets by application micro-X-ray spectral analysis

Abstract

Surface defects of sheet rolled products have a significant impact on its quality, performance and further processing of products, for example, on application of a protective anticorrosive coating. Therefore, the elimination of such defects and their accurate identification is an important aspect of sheet rolling production. Reducing the rejection of metal for surface defects enables to get a significant technical and economic effect. Investigation of the causes of defectiveness of the surface of sheet rolled products will make it possible to determine the source of the appearance of the defects and methods to prevent them. Determination of the nature and morphology of surface defects, the sources of which being metallic and non-metallic inclusions, as well as remnants of slag surface layer, scales from metallurgical and rolling stages, rolled into the surface of a hot-rolled sheet, is often difficult, since the appearance of the defects is very similar. It was shown that application of a scanning electron microscope (SEM) with micro-X-ray spectral analysis (MXSA), thermodynamic analysis makes it possible to determine the chemical composition of micro-areas and associate it with the end-to-end technology of sheet production. The article presents the results of identifying surface defects of cold-rolled sheet steel.