Per: LUCAS CAVALLIERI SELVATICI MARIN (GERDAU - RECIFE), ANDERSON ARAÚJO ALVES GOMES ROCHA (GERDAU), ANDERSON ARAÚJO ALVES GOMES ROCHA (GERDAU)
Abstract:
This study addresses the mitigation of bleed surface defects in billet casting by optimizing negative strip time and ensuring proper alignment of the continuous casting machine. Conducted on a two-strand continuous casting machine with a 4500mm radius and 130mm x 130mm billet section, the work involved analyzing ten heats under two conditions: before and after parameter adjustments and topography corrections. Using tri-axial accelerometer sensors, key oscillation parameters such as amplitude, frequency, and potential lateral/frontal displacements were diagnosed. The negative strip time was calculated considering oscillation frequency, casting speed, and mould stroke. Results showed that pre-adjustment conditions exhibited suboptimal negative strip times, exacerbating the potential defects. Post-adjustment, all casting speeds achieved optimal negative strip times, significantly improving surface quality. Topography analysis identified positioning deviations in the oscillator and withdrawal units, causing vibrations and surface tensions. Aligning these components reduced defect formation. The study concludes that careful adjustment of oscillation parameters and regular topography services are crucial in preventing bleed defects, ensuring high-quality billet production.