# Analysis of the Influence of Segmented Rollers on Slab Bulge Deformation
## 4 Comparisons of Slab Bulge Deformations with Different Segment Rollers
### Bulge Deformation on the Wide Side  
The simulation results of slab bulge deformation along the wide side are shown in Figure 7. The influence of the segmented rollers was numerically analyzed by a comparison between the average values of the bulge deformation. As can be seen in Figure 7, the following conclusions can be drawn:  
(1) In the bulge deformation model with the three-segment rollers, the deformation rapidly increased to 0.90 mm from the edge to the distance of 270 mm in the direction of the wide surface. The deformation of the slab formed into a bulging platform from the distance of 270 mm to the slab center (600 mm) in the wide direction. The value of the bulging platform was 0.90 mm. The reason for this was that the edge of the solidified slab had formed a thick shell of great stiffness, and the deformation was small. The thickness of the shell decreased with the increasing distance, resulting in the decrease of slab stiffness. The bulge deformation of the slab rapidly increased under the hydrostatic pressure. Then, the platform appeared with the uniform thickness and uniform static pressure of the slab. The deformation of the slab at the contact position with the roller sectional area was greater than the average value of the platform. This was because the fixed area of the slab intermittently passed through the sectional area of the segmented rollers, and the positive creep was more effective than the reverse creep in the fixed area. In the continuous casting process, the positive creep makes the solidified shell convex outwards, and the reverse creep makes the solidified shell recess (2) The minimum bulge deformation was 0.82 mm in the model with rigid solid rollers. The maximum bulge deformation of 1.43 mm appeared in the model with elastic solid rollers. The difference between the deformation of the two models was about 0.61 mm, and the increase remained around 74.3%. The results showed that the stiffness of the casting rollers had a great influence on slab bulge deformation. However, the casting rollers cannot be absolutely rigid rollers in the actual production process. Thus, the elastic rollers were more suitable than the rigid rollers to simulate the bulge deformation of the casting slab in the actual production process, as a more accurate result could be obtained.  
(3) The two-segment and three-segment rollers were defined by using elasticity. The bulge deformation of the casting slab in the two-segment roller model was reduced to 1.28 mm in comparison with the elastic solid rollers model. The difference in bulge deformation was 0.15 mm, meaning there was a decrease of 10.5% between the two models, while the bulge deformation of the slab with the three-segment rollers reached 0.90 mm. The bulge deformation difference was 0.53 mm, dropping by 37.1%. The result indicated that the bulge deformation with the three-segment rollers was closer to that of the rigid solid rollers. This means that the bulge deformation of the casting slab could be effectively controlled by using segmented rollers, and the influence of the three-segment rollers was more effective than that of the two-segment rollers.