Optimization of strand and final electromagnetic stirrers of round bloom casters with multiple sections

Abstract

Strand electromagnetic stirring (S-EMS) and final electromagnetic stirring (F-EMS) are the main methods used to improve the center porosity and segregation for round blooms. To optimize the stirring conditions, nail shooting tests were conducted for three sections of large round blooms with diameters of ϕ380 mm, ϕ450 mm, and ϕ600 mm. Acid leaching and sulfur print tests were used to investigate the shell thickness. Based on the results of nail shooting tests, a mathematical model of solidification was established, and the variation of shell thickness and the central solid fraction were exactly calculated by the model. By taking all sections into account, the locations of S-EMS and F-EMS were optimized for each section. In the results, the macro-segregation of various sections is improved after the locations of S-EMS and F-EMS systems are changed.

Keywords

continuous casting / electromagnetic stirring / blooms / mathematical models / optimization

References

[1] Duan K.J., Zhang L., Yuan X.Z., Han S.S., Liu Y., Huang Q.S. Effect of an upward magnetic field on nanosized sulfide precipitation in ultra-low carbon steel. Int. J. Miner. Metall. Mater., 2015, 22(7): 714.

[2] Zhao Z.B., Xu Z., Wang G.S., Zhu Q.F., Cui J.Z. As-cast structure of DC casting 7075 aluminum alloy obtained under dual-frequency electromagnetic field. Int. J. Miner. Metall. Mater., 2014, 21(2): 150.

[3] Li J.C., Wang B.F., Ma Y.L., Cui J.Z. Effect of complex electromagnetic stirring on inner quality of high carbon steel bloom. Mater. Sci. Eng. A, 2006, 425(1-2): 201.

[4] Xiao C., Zhang J.M., Luo Y.Z., Wei X.D., Wu L., Wang S.X. Control of macrosegregation behavior by applying final electromagnetic stirring for continuously cast high carbon steel billet. J. Iron Steel Res. Int., 2013, 20(11): 13.

[5] Liu Y., Wang X.H. Effect of electromagnetic stirring at secondary cooling area on central segregation of a continuously cast slab. J. Univ. Sci. Technol. Beijing, 2007, 29(6): 582.

[6] Li W.J. The Effect of Final Electromagnetic Stirring to Solidification Structure of Bloom [Dissertation], 2014, Anshan, University of Science and Technology Liaoning, 6.

[7] Trindade L.B., Vilela A.C.F., Filho A.F.F., Vilhena M.T., Soares R.B. Numerical model of electromagnetic stirring for continuous casting billets. IEEE Trans. Magn., 2002, 38(6): 3658.

[8] Su W., Jiang D.B., Luo S., Zhu M.Y. Numerical simulation for optimization of F-EMS in billet continuous casting. J. Northeastern Univ. Nat. Sci., 2013, 34(5): 673.

[9] Liu H.P., Xu M.G., Qiu S.T., Zhang H. Numerical simulation of fluid flow in a round bloom mold with in-mold rotary electromagnetic stirring. Metall. Mater. Trans. B, 2012, 43(6): 1657.

[10] Song X.P., Cheng S.S., Cheng Z.J. Mathematical modelling of billet casting with secondary cooling zone electromagnetic stirrer. Ironmaking Steelmaking, 2013, 40(3): 189.

[11] Jang Y., Choi B., Kang B., Hong C.P. Effects of electromagnetic stirring on the microstructure and high-temperature mechanical properties of a hyper-eutectic Al–Si–Cu–Ni alloy. Metall. Mater. Trans. B, 2015, 46(1): 7.

[12] Wu H.J., Wei N., Bao Y.P., Wang G.X., Xiao C.P., Liu J.J. Effect of M-EMS on the solidification structure of a steel billet. Int. J. Miner. Metall. Mater., 2011, 18(2): 159.

[13] Ding N., Bao Y.P., Su Q.S., Wang L.F. Location determination of final electromagnetic stirring and its effect on central carbon segregation for SWRH82B steel. J. Univ. Sci. Technol. Beijing, 2011, 33(1): 17.

[14] Li J.C., Wang B.F., Wang X.D., Pei H.J., Wang S.B. Optimization of stirring position and parameters of final electromagnetic stirring process for continuous casting bloom. Spec. Cast. Nonferrous Alloys, 2014, 34(8): 853.

[15] Kawawa T., Sato H., Miyahara S., Koyano T., Nemoto H. Determination of solidifying shell thickness of continuously cast slab by rivet pin shooting. Tetsu-to-Hagane, 1974, 60(2): 206.

[16] Su W., Wang W.L., Luo S., Jiang D.B., Zhu M.Y. Heat transfer and central segregation of continuously cast high carbon steel billet. J. Iron Steel Res. Int., 2014, 21(6): 565.

[17] Wang R., Bao Y.P., Li Y.H., An H.H. Optimization of secondary cooling in continuous casting of round billet. Metall. Res. Technol., 2015, 112(3): 302.

[18] Luo J.H. The Optimization Study of Secondary Cooling Zone Electromagnetic Stirring Production Process Parameters of Slab [Dissertation], 2008, Anshan, University of Science and Technology Liaoning, 12.

[19] Takahashi T. Solidification and segregation of steel ingot. Iron Steel, 1982, 17(3): 57.

[20] Ogibayashi S., Yamada M., Mukai T., Tezuka M., Hirai M. Continuous Casting Method, 1987