Abstract:
This study aimed to elucidate the formation mechanisms of micro-macrostructural heterogeneities
in the ingot's cortical zone and their transformation into surface defects during heating, plastic deformation, and
rolling processes. The methodology and results of studying the macro- and microstructural and chemical
heterogeneities of ingots and finished rolled sheets are presented. A comparative method of structuralconcentration analysis of metal at the end-to-end metallurgical processing stage of ingot - slab - rolled sheets was
developed. The technique utilizes metallographic methods to study the structure and perform qualitative analysis
of non-metallic inclusions. The research findings indicate that the quality of the rolled sheet surface is
predominantly determined by the physical heterogeneity of the ingot's crust zone, while the internal defects in thin
rolled sheets are largely influenced by the contamination of the metal with non-metallic inclusions. A novel
mechanism is proposed for the transformation of defects in the casting cortical zone into surface and internal
defects in rolled sheets. This study contributes to a deeper understanding of the formation and transformation of
defects during metal processing, enabling the development of strategies for improving the quality of rolled sheets.
Additionally, the study highlights the importance of controlling the physical heterogeneity of the ingot's crust zone
and minimizing non-metallic inclusion contamination to achieve high-quality rolled sheets.
