RESEARCH OF DEFORMATIONS IN FINAL SLABS AT CONTINUOUS CASTING OF STEEL

Abstract

At casting of steel on CCM quality of all ingots is almost identical by creating stable conditions of continuous casting. The fi nal slabs have a defect in the form of the cross-sectional dimensions - the deviation from the desired values. This leads to additional losses of metal in subsequent metallurgical redistribution and reduces the cost of commodity products. The prior studies and publications consider continuous casting technology in the established periods. Transition periods have been poorly studied because there are no simple and reliable methods of investigation of heat exchange of the ingot with the environment during these periods. This article discusses the causes of different widths of the fi nal continuously casted steel slabs. The numerical modeling of the stress-strain state of the ingot after cutting to length it was made. Calculations were performed for ingots made of carbon steel grades. It was established that the asymmetric in length billet thermal fi eld may cause it stress exceeding the yield stress in the temperature range 800 – 900 °C. This leads to the possibility of residual strain and defl ection width of the ingot from the nominal value. Comparison of calculated and experimental data showed that the deviation of the cross-sectional dimensions of slabs occurs for the following reasons: 1. Cooling mode of the tail section of the ingot was not optimal. 2. There was a signifi cant temperature gradient along the length of the end of the ingot. To reduce the different widths of continuously casted steel slabs during the end of the casting it is necessary to improve their cooling technology.