Author Contributions
Conceptualization, M.W. and H.Z.; methodology, M.W., H.Z. and L.X.; software, H.L.; writing—original draft preparation, M.W., H.Z., and H.L.; writing—review and editing, M.W. and H.L.; All authors have read and agreed to the published version of the manuscript.
Funding
This research was funded by National key R&D project of China (No. 2017YFB0304004).
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
Not applicable.
Conflicts of Interest
The authors declare no conflict of interest.
References
- Liu, J.; Wen, G.H.; Tang, P. Research status of transversal crack on micro-alloyed steel slab. J. Iron Steel Res. 2016, 28, 1–9. [Google Scholar]
- Lan, P.; Du, C.W.; Chen, P.L.; Liu, H.S.; Qiu, D.S.; Zhang, J.Q. Research status of surface transverse cracking formation mechanism and control technique for continuously cast microalloyed steels. J. Iron Steel Res. 2017, 29, 1–12. [Google Scholar]
- Du, C.W.; Wang, C.L.; Li, B.; Li, B.; Ma, B.C.; Zhang, J.Q. Effect of the temperature field and cooling rate along casting direction surface transverse crack of microalloyed steel. J. Iron Steel Res. 2018, 30, 523–528. [Google Scholar]
- Konishi, J.; Militzer, M.; Brimacombe, J.K.; Samarasekera, I.V. Modeling the formation of longitudinal facial cracks during continuous casting of hypoperitectic steel. Metall. Mater. Trans. B 2002, 33, 413–423. [Google Scholar] [CrossRef]
- Takeuchi, E.; Brimacombe, J.K. Effect of oscillation-mark formation on the surface quality of continuously cast steel slabs. Metall. Trans. B 1985, 16, 605–625. [Google Scholar] [CrossRef]
- Triolet, N.; Poelmans, K.; Mabelly, P.; Le Papillon, Y. Prevention of corner cracks in slab continuous casting. Rev. Metall. 2009, 106, 508–517. [Google Scholar] [CrossRef]
- Tsuprun, A.Y.; Fedosov, A.V.; Pashchuk, D.V.; Tskitishvili, E.O.; Ottsevich, V.V. Reduction in slab surface corner crack damage due to development of rational secondary cooling regimes. Metallurgist 2014, 57, 824–829. [Google Scholar] [CrossRef]
- Mintz, B.; Yue, S.; Jonas, J.J. Hot ductility of steels and its relationship to the problem of transverse cracking during continuous casting. Int. Mater. Rev. 1991, 36, 187–196. [Google Scholar] [CrossRef]
- Zhu, Z.Y.; Zhen, X.G.; Jiang, H.T.; Li, J.G. Control technology of the transverse cracks in 400 mm ultra-thick slabs. Iron Steel 2011, 46, 33–36. [Google Scholar]
- Zeng, Y.N. Precipitation Mechanism of Second Phase Particles and Control of Surface Cracks in Continuous Casting Slab of Microalloyed Steel; University of Science and Technology Beijing: Beijing, China, 2014. [Google Scholar]
- Ito, Y.; Kato, T.; Yamanaka, A.; Watanabe, T. Improvement of hot ductility in continuously cast strand by ferrite precipitation control. Tetsu-to-Hagan 2003, 10, 1023–1031. [Google Scholar] [CrossRef]
- Kato, T.; Ito, Y.; Kawamoto, M.; Yamanaka, A.; Watanabe, T. Prevention of slab surface transverse cracking by microstructure control. ISIJ Int. 2003, 43, 1742. [Google Scholar] [CrossRef]
- Ito, Y.; Murai, T.; Miki, Y.; Mitsuzono, M.; Goto, T. Development of hard secondary cooling by high-pressure water spray in continuous casting. ISIJ Int. 2011, 51, 1454–1460. [Google Scholar] [CrossRef] [Green Version]
- Du, C.; Zhang, J.; Wen, J.; Li, Y.; Lan, P. Hot ductility trough elimination through single cycle of intense cooling and reheating for microalloyed steel casting. Ironmak. Steelmak. 2016, 43, 331–339. [Google Scholar] [CrossRef]
- Cai, Z.Z.; An, J.Z.; Liu, Z.Y.; Niu, Z.Y.; Zhu, M.Y. Development and application of micro-alloyed steel slab corner transversal crack control technology. J. Iron Steel Res. 2019, 31, 117–124. [Google Scholar]
- Wang, M.L.; Yang, C.Z.; Tao, H.B.; Zhang, H.; Liu, J.H.; Wu, Y.M. Formation mechanism of transverse corner crack on micro-alloyed steel slab. Iron Steel 2012, 47, 27–33, 39. [Google Scholar]
- Cao, J.X.; Tao, H.B.; Zhang, H.; Zhou, M.W.; Zhang, L.Z.; Peng, M.Y. Application of chamfered mould on slab continuous casting production in Lianyuan iron and steel company. Iron Steel 2013, 48, 43–47. [Google Scholar]
- Ren, F.F.; Zhang, H.; Wang, W.N.; Wang, M.L. Numerical simulation of actual temperature field for chamfered mold copper. Iron Steel 2015, 50, 27–33. [Google Scholar]
- Yang, X.S.; Zhang, P. Development and application of chamfered mold technology. Contin. Cast. 2018, 43, 26–31. [Google Scholar]
- Liu, G.L.; Liu, Q.; Ji, C.X.; Chen, B.; Li, H.B.; Liu, K. Application of a novel chamfered mold to suppress corner transverse cracking of micro-alloyed steel slabs. Metals 2020, 10, 1289. [Google Scholar] [CrossRef]
- Muzumdar, D. A consideration about the concept of effective thermal conductivity in continuous casting. ISIJ Int. 1989, 29, 524–528. [Google Scholar] [CrossRef]
- Choudhary, S.K.; Mazumdar, D.; Ghosh, A. Mathematical modeling of heat transfer phenomena in continuous casting of steel. ISIJ Int. 1993, 33, 764–774. [Google Scholar] [CrossRef]
- Tieu, A.K.; Kim, I.S. Simulation of the continuous casting process by a mathematic model. Int. J. Mech. Sci. 1997, 39, 185–192. [Google Scholar] [CrossRef]
- Hardin, R.A.; Liu, K.; Kapoor, A.; Beckermann, C. A transient simulation and dynamic spray cooling control model for continuous steel casting. Metall. Mater. Trans. B 2003, 34, 297–306. [Google Scholar] [CrossRef]
Figure 1.
Dimensions (mm) of high-temperature tensile specimens.
Figure 2.
Schematic diagram of the tensile test process.
Figure 3.
Geometry, mesh system and monitoring points for: (a) conventional slab ( 0°, ); (b) chamfered slab ( 30°, ).
Figure 4.
Schematic drawing of key characteristic positions.
Figure 5.
Transverse corner cracks in a typical micro-alloyed steel of a right-angle slab. (a) Transverse corner cracks; (b) cracks at a distance of 5–15 mm from the corners.
Figure 6.
Microstructure of the crack. (a) Pro-eutectoid ferrite film generated along the grain boundary; (b) enlarged crack morphology.
Figure 7.
Measured phase transformation temperature of S355 steel.
Figure 8.
Measured hot ductility and tensile strength of S355 steel.
Figure 9.
Fracture microstructures from the tensile test at different temperatures. (a) 850 °C, (b) 800 °C, (c) 750 °C, (d) 700 °C, (e) 650 °C.
Figure 10.
Temperature distribution under intensive cooling in foot roller zone of the right-angle slab. (a) The whole process of slab solidification, (b) enlarged view of mould and bending section.
Figure 11.
Temperature distribution under weak cooling in foot roller zone of the right-angle slab. (a) The whole process of slab solidification, (b) enlarged view of mould and bending section.
Figure 12.
Temperature distribution under intensive cooling in foot roller zone of the chamfered slab. (a) The whole process of slab solidification, (b) enlarged view of mould and bending section.
Figure 13.
Temperature distribution under weak cooling in foot roller zone of the chamfered slab. (a) The whole process of slab solidification, (b) enlarged view of mould and bending section.
Table 1.
Chemical composition of typical steel (wt%).
Steel | C | Si | Mn | S | P | Als | N | Ti | Nb | V |
---|
S355 | 0.17 | 0.29 | 1.51 | 0.002 | 0.017 | 0.037 | 0.003 | 0.012 | 0.017 | 0.051 |
Table 2.
Thermophysical properties of S355 steel used in the study.
Parameter | Value |
---|
Density of steel(kg·m−3) | 7020 |
Latent heat of steel (J ·kg−1) | 2.72 × 105 |
Specific heat (J·kg−1·K−1) | 711 |
Thermal conductivity (W·m−1·K−1) | 12.5 + 0.01108 × T |
Liquidus temperature (K) | 1790 |
Solidus temperature (K) | 1728 |
Table 3.
Casting process parameters adopted in the simulation.
Parameter | Value |
---|
Slab transverse section size (mm × mm) | 1600 (Length) × 250 (Thickness) |
Effective mould length (m) | 0.80 |
Initial casting temperature (K) | 1815 |
Casting speed(m·min−1) | 1.0 |
Spraying cooling segment lengthof slab wide face (m) | 0.49, 0.87, 1.061, 1.64, 1.951, 3.906, 5.790 |
Spraying water flow rate of slab wide face (L·min−1) | 451, 610, 211, 254,2 38, 326, 255 |
Spraying cooling length in the foot roller zone (m) | 0.70 |
Spraying water flow rate for an intensive cooling in the foot roller zone (L·min−1) | 150 |
Spraying water flow rate for a weak cooling in the foot roller zone (L·min−1) | 72 |
Cooling water temperature (K) | 300 |
Cooling water flow rate in the mould (m3·h−1) | 420 |
Averaged water temperature rising in mould (°C) | 6.0 |
Table 4.
Temperature of right-angle slab under intensive cooling (°C).
Right-Angle Slab | CornerPoint | Corner5mmPoint | Corner15mmPoint | Corner25mmPoint |
---|
Mould exit (S = 0.8 m) | 754 | 859 | 1014 | 1123 |
Foot roller ending (S = 1.5 m) | 575 | 646 | 785 | 902 |
Beginning of bending (S = 2.52 m) | 734 | 748 | 787 | 844 |
Beginning of straightening (S = 17.16 m) | 834 | 847 | 871 | 897 |
Ending of straightening (S = 19.2 m) | 820 | 832 | 855 | 880 |
Table 5.
Temperature of right-angle slab under weak cooling (°C).
Right-Angle Slab | CornerPoint | Corner5mmPoint | Corner15mmPoint | Corner25mmPoint |
---|
Mould exit (S = 0.8 m) | 754 | 859 | 1014 | 1123 |
Foot roller ending (S = 1.5 m) | 796 | 852 | 957 | 1053 |
Beginning of bending (S = 2.52 m) | 840 | 856 | 896 | 950.1 |
Beginning of straightening (S = 17.16 m) | 842 | 855 | 879 | 906 |
Ending of straightening (S = 19.2 m) | 826 | 839 | 862 | 887 |
Table 6.
Comparation of temperature of chamfered slab under intensive and weak cooling (°C).
Chamfered slab | Intensive Cooling | Weak Cooling |
---|
CornerPoint | Corner5mmPoint | Corner15mmPoint | Corner25mmPoint | CornerPoint | Corner5mmPoint | Corner15mmPoint | Corner25mmPoint |
---|
Mould exit (S = 0.8 m) | 972 | 1015 | 1102 | 1153 | 972 | 1015 | 1102 | 1153 |
Foot roller ending (S = 1.5 m) | 791 | 816 | 904 | 964 | 981 | 1001 | 1064 | 1112 |
Beginning of bending (S = 2.52 m) | 929 | 891 | 901 | 926 | 1016 | 983 | 997 | 1021 |
Beginning of straightening (S = 17.16 m) | 910 | 916 | 931 | 946 | 917 | 924 | 939 | 954 |
Ending of straightening (S = 19.2 m) | 891 | 897 | 912 | 891 | 898 | 905 | 920 | 934 |
| Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. |
© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).