Study on Original Position Statistic Distribution Analysis of Low Alloy Steel Continuous Casting Billet

The homogeneity of low alloy steel continuous casting billets obtained under different technology conditions has been investigated by original position statistic distribution analysis technique. On the basis of systematical analysis of ten thousands of primary optical signals at the corresponding original positions, the quantitative statistic distribution information of each element was obtained. The biggest degrees of segregation of low alloy steel continuous casting billet were accurately calculated according to the quantitative distribution maps of the contents. The weight ratio in different content range was used for a criterion of the homogeneity of the materials, and the criterion was expressed in two parameters including the total weight ratio of contents (the degree of statistic homogeneity, H) within a certain content range (C0±R) and the median value confidence extension ratio(the degree of statistic segregation, S) at 95% of confidence limit of weight ratio. The two parameters reflect the distribution regularity of composition and state for metal materials in a large region. The difference between the sample with high columnar crystal and the sample with high equiaxed crystal has been studied by using the two parameters.