During the continuous casting of advanced high-strength steel slabs, both surface and internal discontinuities are prone to occur. These discontinuities can include cracks, voids, coarse nonmetallic inclusions, and heavy local chemical and microstructural segregation. Many nondestructive testing techniques have been developed to assess the presence of these discontinuities, which correspond to specific “fingerprint” responses in sound wave interactions. The factors responsible for these discontinuities are often related to the mechanical, thermal, or transformation stresses that take place during the solidification of the slabs. The high thermal stresses result from the difference in volume expansion or contraction behavior caused by frequent temperature fluctuations during solidification. In order to study the effect of these temperature fluctuations, a two-dimensional finite element method simulation model was established. In addition, to validate the model results, an ultrasonic testing (UT) system was used to detect and localize the discontinuities caused by thermal or transformation stresses. The results from the UT scanning were assessed with an image processing analysis to identify the size and location of the discontinuities in the slabs. These results were enhanced with a systematic advanced microstructural characterization technique.
Allazadeh, M.R., C.I. Garcia, A. Deardo, and M. Lovell, 2009, “Analysis of Stress Concentration around Inclusions due to Thermally Induced Strain to the Steel Matrix,” Journal of ASTM International, Vol. 6, No. 5, pp. 1–12.
Bernhard, C., H. Hiebler, and M. Wolf, 1996, “Simulation of Shell Strength Properties by the SSCT Test,” ISIJ International, Vol. 36 (Issue Suppl.), pp. s163–s166.
Cabrera, J.M., V. Carreño-Galindo, R.D. Morales, and F. Chávez, 1998, “Macro-Micro Modeling of the Dendritic Microstructure of Steel Billets Processed by Continuous Casting,” ISIJ International, Vol. 38, No. 8, pp. 812–821.
Carpenter, K.R., 2004, “The Influence of Microalloying Elements on the Hot Ductility of Thin Slab Cast Steel,” Master of Engineering thesis, University of Wollongong, Australia.
Chimani, C.M., and K. Mörwald, 1999, “Micromechanical Investigation of the Hot Ductility Behavior of Steel,” ISIJ International, Vol. 39, No. 11, pp. 1194–1197.
Comineli, O., 1998, “The Influence of Cooling Rate and Microalloying Addition of Ti and Nb on the Hot Ductility of HSLA Steels,” Thesis, Department of Mechanical Engineering and Aeronautics, City University, London.
Gove, K.B., and J.A. Charles, 2013, “Further Aspects of Inclusion Deforma-tion,” Metals Technology, Vol. 1, pp. 425–431.
Gur, H., and A.E. Tekkaya, 1996, “Finite Element Simulation of Quench Hardening,” Steel Research, Vol. 67, No.7, pp. 298–306.
Hua, M., C.I. Garcia, and A.J. DeArdo, 1997, “Precipitation Behavior in Ultra-Low-Carbon Steels Containing Titanium and Niobium,” Metallur-gical and Materials Transactions A, Vol. 28A, pp. 1769–1780.
Kim, K., H.N. Han, T.-J. Yeo, Y. Lee, K.H. Oh, and D.N. Lee, 1997, “Analysis of Surface and Internal Cracks in Continuously Cast Beam Blank,” Ironmaking & Steelmaking, Vol. 24, No. 3, pp. 249–256.
Kristiansson, J.O., 1982, “Thermal Stresses in the Early Stage of Solidifica-tion of Steel,” Journal of Thermal Stresses, Vol. 5, No. 3–4, pp. 315–330.
Li, C.-S., and B.G. Thomas, 2004, “Thermomechanical Finite-Element Model of Shell Behavior in Continuous Casting of Steel,” Metallurgical and Materials Transactions B, Vol. 35, pp. 1151–1172.
Ma, F.J., G.H. Wen, P. Tang, G.D. Xu, F. Mei, and W.L. Wang, 2011, “Effect of Cooling Rate on the Precipitation Behavior of Carbonitride in Microalloyed Steel Slab,” Metallurgical and Materials Transactions B, Vol. 42, No. 1, pp. 81–86.
Ma, F.J., G.H. Wen, P. Tang, X. Yu, J.Y. Li, G.D. Xu, and F. Mei, 2010a, “Causes of Transverse Corner Cracks in Microalloyed Steel in Vertical Bending Continuous Slab Casters,” Ironmaking & Steelmaking, Vol. 37, No. 1, pp. 73–79.
Ma, F.J., G.H. Wen, P. Tang, X. Yu, J.Y. Li, G.D. Xu, and F. Mei, 2010b, “In Situ Observation and Investigation of Effect of Cooling Rate on Slab Surface Microstructure Evolution in Microalloyed Steel,” Ironmaking & Steelmaking, Vol. 37, No. 3, pp. 211–217.
Mintz, B., and J.M. Arrowsmith, 1979, “Hot-Ductility Behaviour of C-Mn-Nb-Al Steels and Its Relationship to Crack Propagation During the Straightening of Continuously Cast Strand,” Metals Technology, Vol. 6, No. 1, pp. 24–32.
Moon, S.-C., 2003, “The Influence of Austenite Grain Size on Hot Ductility of Steels,” Master of Engineering thesis, University of Wollon-gong, Australia.
Ouispe, A., S.F. Medina, and P. Valles, 1997, “Recrystallization-Induced Precipitation Interaction in a Medium Carbon Vanadium Microalloyed Steel,” ISIJ International, Vol. 37, No. 8, pp. 783–788.
Savage, J., and W.H. Pritchard, 1954, “The Problem of Rupture of the Billet in the Continuous Casting of Steel,” Journal of the Iron and Steel Institute, Vol. 178, No. 27, pp. 269–277.
Shi, C.-B., W.-J. Liu, J. Li, and L. Yu, 2016, “Effect of Boron on the Hot Ductility of Low-Carbon Nb-Ti-Microalloyed Steel,” Materials Transac-tions, Vol. 57, No. 5, pp. 647–653.
Thomas, B.G., 2001, “Continuous Casting,” in The Encyclopedia of Mate-rials: Science and Technology, Vol. 2, pp. 1595–1599.
Wang, W., M. Zhu, Z.-Z. Cai, S. Luo, and C. Ji, 2012, “Micro-Segregation Behavior of Solute Elements in the Mushy Zone of Continuous Casting Wide-Thick Slab,” Steel Research International, Vol. 83, No. 12, pp. 1–10.
Weisgerber, B., M. Hecht, K. Harste, H. Morland, M. Kandel, and J.-Y. Lamant, 2002, “Improvement of Surface Quality on Peritectic Steel Slabs,” Steel Research, Vol. 73, No. 1, pp. 15–19.
Won, Y.M., H.N. Han, T.-J. Yeo, and K.H. Oh, 2000, “Analysis of Solidifi-cation Cracking Using the Specific Crack Susceptibility,” ISIJ International, Vol. 40, No. 2, pp. 129–136.
Won, Y.M., K.-H. Kim, T.-J. Yeo, and K.H. Oh, 1998, “Effect of Cooling Rate on ZST, LIT and ZDT of Carbon Steels near Melting Point,” ISIJ International, Vol. 38, No. 10, pp. 1093–1099.
Yamanaka, A., K. Nakajima, and K. Okamura, 1995, “Critical Strain for Internal Crack Formation in Continuous Casting,” Ironmaking & Steel-making, Vol. 22, No. 6, pp. 508–512.
Zhao, S., D. Wei, R. Li, and L. Zhang, 2014, “Effect of Cooling Rate on Phase Transformation and Microstructure of Nb Ti Microalloyed Steel,” Materials Transactions, Vol. 55, No. 8, pp. 1274–1279.
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