Three Dimensional Methodology to Characterize Large Dendritic Equiaxed Grains in Industrial Steel Ingots

Marvin Gennesson (1, 2, 3) , Julien Zollinger (2, 1) , Dominique Daloz (2, 1) , Bernard Rouat (2, 1) , Joëlle Demurger (3) , Hervé Combeau (2, 1)

1 Labex DAMAS
2 IJL - Institut Jean Lamour
3 ASCOMETAL - ASCOMETAL CREAS

The primary phase grain size is a key parameter to understand the formation of the macrosegregation pattern in large steel ingots. Most of the characterization techniques use two-dimensional measurements. In this paper, a characterization method has been developed for equiaxed dendritic grains in industrial steel castings. A total of 383 contours were drawn two-dimensionally on twelve 6.6 cm 2 slices. A three-dimensional reconstruction method is performed to obtain 171 three-dimensional grains. Data regarding the size, shape and orientation of equiaxed grains is presented and thereby shows that equiaxed grains are centimeter-scale complex objects. They appear to be a poly-dispersed collection of non-isotropic objects possessing preferential orientations. In addition, the volumetric grain number density is 2.2 × 10 7 grains/m 3 , which compares to the 0.5 × 10 7 grains/m 3 that can be obtained with estimation from 2D measurements. The 2.2 × 10 7 grains/m 3 value is ten-times smaller than that previously used in the literature to simulate the macrosegregation profile in the same 6.2 ton ingot.

Mots clés: steel; dendritic grain size; industrial ingot

Domaines: Matériaux

Marvin Gennesson, Julien Zollinger, Dominique Daloz, Bernard Rouat, Joëlle Demurger, et al.. Three Dimensional Methodology to Characterize Large Dendritic Equiaxed Grains in Industrial Steel Ingots. Materials, 2018, 11 (6), pp.1007. ⟨10.3390/ma11061007⟩. ⟨hal-02050983⟩