Study on the three-dimensional morphology of MnS inclusions in high sulphur steel

MnS inclusions in steels usually have many kinds of morphology. It is difficult to accurately obtain the characteristics of inclusions by two-dimensional observation due to the complex morphology of sulphides in steel, especially the type II MnS inclusions. In this study, the three-dimensional morphology of sulphide in high sulphur steel was investigated by using non-aqueous solution electrolytic etching. Inclusions with a circle and ellipse morphology in two-dimension show more complex morphology in three-dimension. The differences in the distribution, size, shape of sulphides between the two-dimensional and three-dimensional state in the high sulphur steel were studied. Compared with the statistical results of inclusions in two-dimension, the diameter and area in three-dimension are larger than those in two-dimension. Moreover, the proportional function between the size of inclusion in two-dimension and that in three-dimension is proposed.