Quantitative Model of Hereditary Behavior for Carbon Segregation in Continuous Casting Billets Based on Grayscale Analysis

To obtain a reliable hereditary law of carbon segregation, the carbon element content in the entire area of the longitudinal sections of billet, wire rod and bolt samples is quantitatively calculated through the method of metal macrostructure grayscale analysis (MGA). Based on the calculation results, the hereditary behavior of carbon distribution characteristics at the “geometric similar” positions of the selected samples is quantitatively analyzed from three aspects: carbon element content, longitudinal carbon fluctuation and transverse carbon uniformity. The results show that the distribution characteristics of the carbon element content and carbon variation coefficient on the longitudinal sections of the selected samples are approximately the same, which can quantitatively reflect the hereditary behavior of the carbon segregation, and the corresponding hereditary equations during the rolling process are fitted. Then, the central segregation index, which can represent the transverse carbon uniformity, on the longitudinal sections of selected samples is calculated, and the corresponding hereditary equation is also obtained. According to the hereditary equation of central segregation index during the rolling process, to produce rolled products with more uniform quality and mechanical properties, the central segregation index of the corresponding billet should be controlled below 1.05.