Modeling Defect Formation Processes at Different Stages of Metallurgical Production

The paper proposes models for predicting the appearance of surface defects in flat-rolled steel production at ferrous metallurgy enterprises. A “shell” type surface defect is considered. At the complete cycle metallurgical enterprises with flat-rolled steel production, the quality of the finished product is affected by the various stages of production. In particular, the appearance of the “shell” type defect may influence the quality of the starting material, namely slabs. Therefore, one of the proposed models is a model of the cracks occurrence in continuous steel casting process. The model uses a criterion based on the time the ingot is in the curvilinear zone of the continuous steel casting facility (CSSF) with the crust temperature in the range of the embrittlement temperature of the corresponding steel grades. In the process of cold rolling, the “shell” type defect is shaped. It can be completely rolled out or appear as a surface defect in cold rolling. Therefore, the next model considered in the paper is a model of defect shaping in the process of cold rolling. The stress-strain state in the defect zone is modeled, and the influence of initial geometrical characteristics and rolling modes on the degree of rolling-out were analyzed.