Study On The Mold Taper Of Bloom Continuous Casting For Gear Steel20CrMnTi

With the advancement of the casting process, taper is one of the most important design parameters of mold, the rational design of taper has great influence on the life of the mold and bloom quality. The appropriate taper not only can improve the cooling effect of mold, reduce the possibility of steel-leakage accident, but also help to prevent and reduce the vertical slab crack. In this study, the mold taper of280mm×280mm billets was optimized by finite element analysis software ANSYS.Firstly, a2D non-steady-state thermal-mechanical coupled model is employed to simulate the solidification processes for gear steel20CrMnTi in the bloom continuous casting under different casting speeds and super heats. The results show that the surface temperature of bloom is higher, the shell’s thickness in casting solidification is thinner, the stress is lower, the shrinkage of bloom is decreased when the superheat is increased at the same casting speeds or the casting speeds is increased at the same superheat. In addition, the results show that surface temperature increased slightly, shell shrinkage has less change and the shell’s thickness in casting solidification is thinner as change of superheat degree from15℃to25℃at the same casting speed. After comparison, the change of super heats has smaller influence on bloom solidification than casting speeds.Secondly, a3D steady-state model of the mold is employed to simulate the temperature distribution and the distortion of the mold with different casting speeds and super heats. The result shows that the temperature and the distortion of the mold hot and cold face are higher as the increase of casting speeds. The temperature and the distortion of the mould is almost same with the change of super heats.Finally, based on the bloom shrinkage and the mould deformation, the taper of the mold is designed under different casting speeds and super heats. The study shows that the casting speeds has great influence on the taper of the mold, and the mold needs minor taper with the increase of casting speeds. And the taper changes slightly with the change of super heats. And this paper also compares the difference between center taper and corner taper of the mold, the result show that corner taper is steeper at the upper half of the mold, whereas the taper at the bottom half of mold is little difference.