Shape of slab solidification end under non-uniform cooling and its influence on the central segregation with mechanical soft reduction

Jie Li; Yan-hui Sun; Hang-hang An; Pei-yuan Ni

doi:10.1007/s12613-020-2089-x

Volume 28 Issue 11

Nov. 2021

Turn off MathJax

Article Contents

Article Navigation > International Journal of Minerals, Metallurgy and Materials > 2021 > 28(11): 1788-1798

Jie Li, Yan-hui Sun, Hang-hang An, and Pei-yuan Ni, Shape of slab solidification end under non-uniform cooling and its influence on the central segregation with mechanical soft reduction, Int. J. Miner. Metall. Mater., 28(2021), No. 11, pp. 1788-1798. https://doi.org/10.1007/s12613-020-2089-x

Cite this article as:

Jie Li, Yan-hui Sun, Hang-hang An, and Pei-yuan Ni, Shape of slab solidification end under non-uniform cooling and its influence on the central segregation with mechanical soft reduction, Int. J. Miner. Metall. Mater., 28(2021), No. 11, pp. 1788-1798. https://doi.org/10.1007/s12613-020-2089-x

Citation:

PDF( 1726 KB)

Research Article

Shape of slab solidification end under non-uniform cooling and its influence on the central segregation with mechanical soft reduction

+ Author Affiliations

Corresponding author:
Yan-hui Sun E-mail: sunyanhui@metall.ustb.edu.cn
Received: 25 March 2020; Revised: 3 May 2020; Accepted: 6 May 2020; Available online: 9 May 2020

Abstract

Abstract

In order to study the effect of continuous casting process parameters on the shape of slab solidification end under non-uniform cooling, a solidification model of a continuous-cast slab with non-uniform cooling condition was established with ProCAST software. The model was verified by the results of nail shooting tests and the infrared temperature measurement equipment. Four characteristic parameters were defined to evaluate the uniformity of the shape of slab solidification end. The results showed that the nonuniformity at the beginning and end of solidification, the solidification end length, and the solidification unevenness increased with the rise of casting speed. For each 10°C increase of superheat, the solidification unevenness increased by about 0.022. However, the effect of superheat on the solidification end length can be ignored. The secondary cooling strength showed minimal effect on the nonuniformity at the beginning and end of solidification. With the increase in secondary cooling intensity, the solidification end length decreased, but the solidification unevenness increased. In addition, the central segregation of the slab produced with and without the mechanical soft reduction (MSR) process was investigated. The transverse flow of molten steel with low solid fraction influenced the central segregation morphology under MSR.
- continuous casting;
- heat transfer model;
- nail shooting;
- shape of solidification end;
- central segregation

FullText(HTML)

Supplements(0)

References(34)

References

[1]	M.C. Flemings, Our understanding of macrosegregation: Past and present, ISIJ Int., 40(2000), No. 9, p. 833. doi: 10.2355/isijinternational.40.833
[2]	Z. Chen and H.F. Shen, Simulation of macrosegregation in a 36-t steel ingot using a multiphase model, Int. J. Miner. Metall. Mater., 27(2020), No. 2, p. 200. doi: 10.1007/s12613-019-1875-9
[3]	X.G. Zhang, K. Matsuura, and M. Ohno, Abnormal grain growth in austenite structure reversely transformed from ferrite/pearlite-banded structure, Metall. Mater. Trans. A, 45(2014), No. 10, p. 4623. doi: 10.1007/s11661-014-2364-4
[4]	T.F. Majka, D.K. Matlock, and G. Krauss, Development of microstructural banding in low-alloy steel with simulated Mn segregation, Metall. Mater. Trans. A, 33(2002), No. 6, p. 1627. doi: 10.1007/s11661-002-0172-8
[5]	G. Krauss, Solidification, segregation, and banding in carbon and alloy steels, Metall. Mater. Trans. B, 34(2003), No. 6, p. 781. doi: 10.1007/s11663-003-0084-z
[6]	Y.S. Han, W. Yan, J.S. Zhang, W.Q. Chen, J. Chen, and Q. Liu, Optimization of thermal soft reduction on continuous-casting billet, ISIJ Int., 60(2020), No. 1, p. 106. doi: 10.2355/isijinternational.ISIJINT-2019-409
[7]	Y. Chen, M.F. Xiao, and G.R. Wu, Dynamic soft reduction technology for bloom casting, J. Iron Steel Res. Int., 17(2010), No. 6, p. 1. doi: 10.1016/S1006-706X(10)60104-5
[8]	Z.W. Han, D.F. Chen, K. Feng, and M.J. Long, Development and application of dynamic soft-reduction control model to slab continuous casting process, ISIJ Int., 50(2010), No. 11, p. 1637. doi: 10.2355/isijinternational.50.1637
[9]	M. Vynnycky, Applied mathematical modelling of continuous casting processes: A review, Metals, 8(2018), No. 11, art. No. 928. doi: 10.3390/met8110928
[10]	J. Zeng, W.Q. Chen, Q.X. Wang, and G.S. Wang, Improving inner quality in continuous casting rectangular billets: Comparison between mechanical soft reduction and final electromagnetic stirring, Trans. Indian Inst. Met., 69(2016), No. 8, p. 1623. doi: 10.1007/s12666-015-0742-2
[11]	A.N. Zavalishchin, M.I. Rumyantsev, D.N. Chikishev, M.V. Efremova, and E.V. Kozhevnikova, Influence of "soft" reduction on the structure of continuous cast ingot and the properties of rolled products of microalloyed steels, Metallurgist, 63(2019), No. 3-4, p. 238. doi: 10.1007/s11015-019-00817-8
[12]	L. Li, X. Zhao, P. Lan, Z.P. Tie, H.Y. Tang, and J.Q. Zhang, Effect of roll surface profile on thermal-mechanical behavior of continuously cast bloom in soft reduction process, [in] TMS 2019 148th Annual Meeting & Exhibition Supplemental Proceedings, Springer, Cham, 2019, p. 93.
[13]	R. Thome and K. Harste, Principles of billet soft-reduction and consequences for continuous casting, ISIJ Int., 46(2006), No. 12, p. 1839. doi: 10.2355/isijinternational.46.1839
[14]	C.H. Yim, J.K. Park, B.D. You, and S.M. Yang, The effect of soft reduction on center segregation in C.C. slab, ISIJ Int., 36(1996), No. Suppl, p. S231. doi: 10.2355/isijinternational.36.Suppl_S231
[15]	M. Jauhola and M. Haapala, The latest results of dynamic soft reduction in slab CC-machine, [in] 83rd Steelmaking Conference Proceedings, Pittsburgh, 2000, p. 201.
[16]	C. Ji, S. Luo, M.Y. Zhu, and Y. Sahai, Uneven solidification during wide-thick slab continuous casting process and its influence on soft reduction zone, ISIJ Int., 54(2014), No. 1, p. 103. doi: 10.2355/isijinternational.54.103
[17]	Y. Ito, A. Yamanaka, and T. Watanabe, Internal reduction efficiency of continuously cast strand with liquid core, Rev. Met. Paris, 97(2000), No. 10, p. 1171. doi: 10.1051/metal:2000104
[18]	M.H. Wu, J. Domitner, and A. Ludwig, Using a two-phase columnar solidification model to study the principle of mechanical soft reduction in slab casting, Metall. Mater. Trans. A, 43(2012), No. 3, p. 945. doi: 10.1007/s11661-011-0940-4
[19]	J. Domitner, M.H. Wu, A. Kharicha, A. Ludwig, B. Kaufmann, J. Reiter, and T. Schaden, Modeling the effects of strand surface bulging and mechanical softreduction on the macrosegregation formation in steel continuous casting, Metall. Mater. Trans. A, 45(2014), No. 3, p. 1415. doi: 10.1007/s11661-013-2060-9
[20]	B. Rogberg and L. Ek, Influence of soft reduction on the fluid flow, porosity and center segregation in CC high carbon- and stainless steel blooms, ISIJ Int., 58(2018), No. 3, p. 478. doi: 10.2355/isijinternational.ISIJINT-2017-534
[21]	Z.Z. Cai and M.Y. Zhu, Non-uniform heat transfer behavior during shell solidification in a wide and thick slab continuous casting mold, Int. J. Miner. Metall. Mater., 21(2014), No. 3, p. 240. doi: 10.1007/s12613-014-0901-1
[22]	D.P. Li, H.Z. Wu, H.F. Wang, and H. Li, Growth of solidified shell in bloom continuous casting mold of hypo-peritectic steel based on a FeS tracer method, J. Iron Steel Res. Int., 27(2020), No. 7, p. 782. doi: 10.1007/s42243-020-00394-0
[23]	M.J. Long, Z.H. Dong, D.F. Chen, Q. Liao, and Y.G. Ma, Effect of uneven solidification on the quality of continuous casting slab, Int. J. Mater. Prod. Technol., 47(2013), No. 1/2/3/4, p. 216. doi: 10.1504/IJMPT.2013.058956
[24]	H. Preßlinger, S. Ilie, P. Reisinger, A. Schiefermüller, A. Pissenberger, E. Parteder, and C. Bernhard, Methods for assessment of slab centre segregation as a tool to control slab continuous casting with soft reduction, ISIJ Int., 46(2006), No. 12, p. 1845. doi: 10.2355/isijinternational.46.1845
[25]	S.K. Choudhary, S. Ganguly, A. Sengupta, and V. Sharma, Solidification morphology and segregation in continuously cast steel slab, J. Mater. Process. Technol., 243(2017), p. 312. doi: 10.1016/j.jmatprotec.2016.12.030
[26]	P. Fei, Y. Min, C.J. Liu, and M.F. Jiang, Effect of continuous casting speed on mold surface flow and the related near-surface distribution of non-metallic inclusions, Int. J. Miner. Metall. Mater., 26(2019), No. 2, p. 186. doi: 10.1007/s12613-019-1723-y
[27]	J. Savage and W.H. Pritchard, The problem of rupture of the billet in the continuous casting of steel, J. Iron Steel Inst., 178(1954), No. 3.
[28]	S. Louhenkilpi, J. Miettinen, and L. Holappa, Simulation of microstructure of as-cast steels in continuous casting, ISIJ Int., 46(2006), No. 6, p. 914. doi: 10.2355/isijinternational.46.914
[29]	T. Nozaki, J.I. Matsuno, K. Murata, H. Ooi, and M. Kodama, A secondary cooling pattern for preventing surface cracks of continuous casting slab, Trans. Iron Steel Inst. Jpn., 18(1978), No. 6, p. 330. doi: 10.2355/isijinternational1966.18.330
[30]	J.S. Ha, J.R. Cho, B.Y. Lee, and M.Y. Ha, Numerical analysis of secondary cooling and bulging in the continuous casting of slabs, J. Mater. Process. Technol., 113(2001), No. 1-3, p. 257. doi: 10.1016/S0924-0136(01)00654-9
[31]	R.A. Hardin, K. Liu, C. Beckermann, and A. Kapoor, A transient simulation and dynamic spray cooling control model for continuous steel casting, Metall. Mater. Trans. B, 34(2003), No. 3, p. 297. doi: 10.1007/s11663-003-0075-0
[32]	M.J. Long, D.F. Chen, Q.X. Wang, D.H. Luo, Z.W. Han, Q. Liu, and W.X. Gao, Determination of CC slab solidification using nail shooting technique, Ironmaking Steelmaking, 39(2012), No. 5, p. 370. doi: 10.1179/1743281211Y.0000000088
[33]	C. Ji, S. Luo, and M.Y. Zhu, Analysis and application of soft reduction amount for bloom continuous casting process, ISIJ Int., 54(2014), No. 3, p. 504. doi: 10.2355/isijinternational.54.504
[34]	M. Réger, B. Verő, R. Józsa, and Z. Csepeli, Effect of mushy zone permeability on the formation of centerline segregation in slab casting, Mater. Sci. Forum, 790-791(2014), p. 296. doi: 10.4028/www.scientific.net/MSF.790-791.296