Grooved Mold Newborn Solidified Shell Coupled Thermal Simulation Studies

In this paper ,a two-dimensional fully thermo-mechanical coupled finite element model is established to analyze the solidification process of continuous casting slabs in mold and stress distributions in the solidified shells and deformation of shells. In the model ,Temperature-dependent functions are employed for important properties of steel, and rate-dependent elastic-visco-plastic model is used. The model is implemented with Marc software on the computer . The distributions of temperature , stresses, thickness and deformation of the solidified shells are obtained .The simulation results indicate that the heat flux is remarkably reduced when air gap is formed at the slab corner, and a hot spot region is formed at the off-corner of slab , in the region ,the shell thickness is the thinnest and the surface temperature is the highest. The off-corner hot spot region is sensitive to crack ,which is likely to form cracks .The calculated shell thickness accords with that of breakout shell measurement.On the bases of the first model ,groove-mold models are established .Parallel grooves of different space is scored on the inner surface of the mold along the longitudinal direction .All parameters in the first model is used except the mesh. All models are implemented on the computer . The results show that the influence of gap on the heat transfer of mold is reduced remarkably by grooves. The shape of the shells at a initial time is compared , when the space is smaller ,the degree of equality of the shell is higher ,the space is smaller, the front of solidifying go to flat at a earlier time. When the shell is formed in the casting mold , the isolines of stress in the shell's near-surface region is much denser than others . Equivalent stress in the region is higher than others .When grooves is scored on the mold inner surface , equivalent stress in the shell near-surface region is much smaller at a same initial time. The difference of stress distributions between regions is much smaller than flat mold model . When the space is about 25 mm, equivalent stress in the shell near-surface region reduce sharply, and then a rise follows , when the space is reduced to 13 mm ,the stress has a great fall .Thinking about the uniformity of shell and stress at the same time ,When the space is smaller than 13mm , it is beneficial to the uniformity of heat transfer between the mold and the shell, and to the uniformity of shell growth, the chance of cracking is reduced.