Effect of superheat on macrostructure and macrosegregation in continuous cast low-alloy steel slabs

4th International Conference on Advances in Solidification Processes

材料科学;物理学

Pikkarainen, T.^1,2 ; Vuorenmaa, V.^2 ; Rentola, I.^2 ; Leinonen, M.^2 ; Porter, D.^1

Centre for Advanced Steels Research, University of Oulu, P.O. Box 4200, Oulu

FI-90014, Finland^1

Ruukki Metals Oy, Rautaruukintie 155, Raahe, Finland^2

关键词: Columnar to equiaxed transition;    Dendritic structures;    Globular structure;    Grain sedimentations;    Low alloyed steels;    Macrosegregations;    Negative segregations;    Through-thickness;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/117/1/012064/pdf
DOI  :  10.1088/1757-899X/117/1/012064

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The effect of superheat on grain sedimentation and macrosegregation has been investigated using experimental castings of a low-alloyed steel grade. With a high superheat of ∼ 40 °C, the central equiaxed parts of the slabs consisted of randomly oriented fine dendrites but with a low superheat of ∼ 10 °C, coarse globular structures formed. The mean carbon content measured with optical emission spectroscopy was of the order of 15% smaller with coarse globular structures than in fine equiaxed dendritic structures. Electron probe microanalysis of other alloying elements indicates that the negative segregation in the slab central zones is caused by sedimentation of globulites. With superheat in the range ∼ 20 - 40 °C, the equiaxed zone is bordered by a columnar to equiaxed transition (CET) zone. In this region a positive macrosegregation of carbon and other alloying elements was observed. These phenomena are important when considering the through-thickness properties of the slabs and final products.