**8. Conclusion**

578 Numerical Simulation – From Theory to Industry

at 1150 s. ( FU JianXun et al. 2010(c))

the height of the caster.

broadening.

casting speed, and the constitution of the caster.

relaxed, reduces hardness, and enhances plasticity.

under the pressure of static molten steel at high temperature. The creep rate depends on the composition of the compound metal, and the processes of refining and thermal treatment. Creep deformation causes slab broadening because it makes the material keep stress

 **Figure 17.** (a) Deformation of slab in the direction of thickness at 230 mm; (b) Temperature field of slab

(a) (b)

The amount of broadening depends on the forces acting on the slab and the properties of the slab material, especially those at high temperature. Specifically, it depends on the static pressure of molten steel, the high-temperature mechanical properties of steel, the composition of the slab material, the thickness of the slab shell, secondary cooling intensity,

The static pressure of molten steel is the driving force for the deformation of the slab shell. It is related to the type and constitution of caster. At present, vertical-bending casters are most common. For these casters, the static pressure is related to the density of molten steel and

Under the conditions of high casting speed and constant cooling water, the fully solidified zone extend, the length of molten core increases, and the shell becomes thinner. Because of the higher temperature, the slab shell also has lower yield strength and better malleability. Consequently, the slab broadening increases. However, if the cooling water supply is

The effects of steel grade on the broadening result from differences in material properties at high temperature, and hence differences in resistance to plastic deformation and creep deformation. With an increase in the carbon percentage, the ratio of ferrolite and austenite in the two phase regions changes. The increase in austenite is helpful to the reduction of slab

Intracell dislocation climb and intercell slide are two forms of creep deformation. Solution strengthening, precipitation strengthening, and dispersion strengthening insert a lot of defects into the crystal structure of steel, which hinder dislocation movement and thus

changed when the casting speed is increased, the problem will become sophisticated.

