Evolution of Nonmetallic Inclusion during Steelmaking Process of Cold Heading Steel SWRCH35K
- 1 No. 2 Steel-Making Plant, Jiangsu Yonggang Group Co., Ltd., Zhangjiagang, China
- 2 Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, China
- 3 Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, China
Abstract
In order to analyze the evolution of the inclusions in the cold heading steel SWRCH35K during the steelmaking process, a systematic sampling of the steelmaking processes in a steel plant was carried out. Both SEM-EDS and the image processing software Image-Pro-Plus6.0 were employed to analyze the chemical composition, morphology, quantity and size of non-metal inclusions in the steel samples. The results show that from BOF tapping to continuous casting tundish, the composition of inclusions in SWRCH35K steel changes from Al 2 O 3 → MgO·Al 2 O 3 → CaO-MgO-Al 2 O 3 -CaS, and the typical morphology of the inclusions in the steel gradually changes from irregular blocks and clusters to spherical. The number of inclusions in the BOF argon blowing station is the largest, 213 # /mm 2 , while the number of inclusions at the end of LF refining is the least, about 12 # /mm 2 , and there are basically no inclusions above 5 μm. In addition, LF calcium treatment will adversely affect the size and quantity control of inclusions in steel. In order to effectively reduce the large-size calcium-containing spherical oxide inclusions in cold heading steel, it is necessary to find a technical method that can replace LF calcium treatment to solve the problem of molten steel continuous casting.
- James, M. and William, F. (2002) Spheroidization Cycles for Medium Carbon Steels. Metallurgical and Materials Transactions A, 33, 1255-1261. https://doi.org/10.1007/s11661-002-0226-y
- Ma, X., Humphreys, A.O., Nemes, J., Hone, M., Nickoletopoulos, N. and Jonas, J. (2004) Effect of Microstructure on the Cold Headability of a Medium Carbon Steel. ISIJ International, 44, 905-913. https://doi.org/10.2355/isijinternational.44.905
- Madhuri, V., Gobinath, R. and Balachandran, G. (2019) Effect of Carbon on the Microstructure and Mechanical Properties in Wire Rods Used for the Manufacture of Cold Heading Quality Steels. Transactions of the Indian Institute of Metals, 72, 155-166. https://doi.org/10.1007/s12666-018-1470-1
- Li, J., Yang, S., Li, J. and Chou, Y. (2019) Cause Analysis and Improvement of Cracking of Cold Heading Steel. China Metallurgy, 29, 19-23. (In Chinese) https://doi.org/10.13228/j.boyuan.issn1006-9356.20180242
- Liu, Z., Pei, P. and Ai, L. (2008) Analysis of Cracking Reasons in the Cold Heading Process of SWRCH35K Steel. Iron Steel Vanadium Titanium, 29, 55-59+66. (In Chinese)
- Deng, X., Su, D., Ma, J., Jin, H. and Feng, J. (2012) LF Refining Slag Optimization of Low Carbon Heading Steel. Steelmaking, 28, 13-15+19. (In Chinese)
- Dong, L., Chen, W., Qi, F., Li, W. and Wang, G. (2010) Effect of Calcium Treatment on Inclusions in Cold Heading Steel Containing Aluminum. Special Steel, 31, 32-34. (In Chinese)
- Gao, Z., Liang, H., Wu, J., Hu, Y., Li, S. and Du, S. (2007) Effect of Calcium Treatment on the Cleanliness of Low Carbon Cold Heading Steel. Journal of University of Science and Technology Beijing, 29, 785-788. (In Chinese) https://doi.org/10.13374/j.issn1001-053x.2007.08.007
- Lu, P., Wu, H. and Yue, F. (2014) Change Behavior of Inclusions in High Strength Cold Heading Steel during LF Refining. Steelmaking, 30, 14-17+65. (In Chinese)
- Zhao, J., Cai, X., Ma, J., Li, J. and Zhang, L. (2021) Improvement on Mechanism of Nozzle Clogging Caused by CaS Inclusions in Al-Killed Cold Heading Steel. Iron and Steel, 56, 80-87. (In Chinese) https://doi.org/10.13228/j.boyuan.issn0449-749x.20200604
- Wang, Q., Zhu, H., Sun, J., Duan, Y., Han, P. and Xue, Z. (2020) Formation and Evolution Behavior of Non-Metallic Inclusions in SWRCH45K Cold Heading Steel. China Metallurgy, 30, 41-46. (In Chinese) https://doi.org/10.13228/j.boyuan.issn1006-9356.20200147