The process of drawing thin carbon steel wires through conical dies is used as an experimental method for determining the effect of frictional conditions and die angle on the generation of fine grain layers in the vicinity of the friction surface. In this study, a quantitative criterion for determining the thickness of fine grain layers is proposed. The criterion is based on the coefficient of anisotropy that characterizes the shape of grains. It is shown that fine grain layers are generated under all frictional conditions investigated, but the thickness of the layer depends on these conditions and die angle.

Fine grain layers that generate near frictional interfaces in metal forming processes affect the quality of products. The present paper aims to contribute to the continuum-mechanics-based phenomenological approach for predicting such layers’ properties. In particular, it studies the generation of fine grain layers in the process of multipass drawing of thin high carbon steel wires experimentally. The wires are drawn in three passes under different friction conditions. All three dies in each multipass process have the same semiangle. In total, two die semiangles are used, 4° and 5°. The effects of such processing conditions as the die semiangle, the number of passes, and the friction conditions on the thickness of fine grain layers are observed and discussed. The criterion for determining this thickness is based on the coefficient of anisotropy. Under soft friction conditions, the fine grain layer’s thickness decrease occurs during the consequential passes independently of the die semiangle. On the other hand, in the case of hard friction conditions, the thickness may or may not be a monotonic function of the number of passes, and its general qualitative behavior depends on the die semiangle.

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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.