Affiliation:
1. National University of Science and Technology “MISiS”
2. National University of Study and Technology MISIS
Abstract
The results of assessment of macrostructure and surface quality of round blooms 455 mm in diameter, cast on 4-strand continuous casting machine (CCM) at JSC “Ural Steel” are presented. The analysis of technological casting parameters of round blooms 455 mm in diameter (from steel grade “2”) at bloom caster of JSC “Ural Steel” are completed. Violations in casting temperature and rate parameters, which deteriorate thermal conditions of solidification and quality of continuous casting blooms, have been revealed. The main causes of unsatisfactory bloom quality have been determined, which are the increased overheating of cast metal and irrational secondary cooling mode. The results of the experiment to evaluate the surface temperature dynamics of a round bloom in the secondary cooling zone are presented, which confirmed the inefficiency of the secondary cooling mode for the defect-free bloom formation. As a result of thermal calculations of round blooms solidification of 455 mm in diameter, rational coolant flow rates by secondary cooling sections for bloom caster of JSC “Ural Steel” have been proposed. Optimized secondary cooling parameters provide a softer secondary cooling of the round bloom, which reduces the probability of the surface and internal defects development.
Publisher
Trans Tech Publications, Ltd.
Subject
Condensed Matter Physics,General Materials Science,Radiation
Reference25 articles.
1. G. Vandrunen, et al., Internal cracks in strand-cast blooms, Ironmaking & Steelmaking. 2(2) (1975) 125-133.
2. J. Wu, W. Xu, Y.D. Yang, Technics study of reducing longitudinal surface crack of beam blank, Iron Steel. 44(10) (2009) 95-97.
3. J. Zhang et al., Effects of an even secondary cooling mode on the temperature and stress fields of round bloom continuous casting steel, Journal of Materials Processing Technology. 222 (2015) 315-326.
4. W. Chen, Y.-Z. Zhang, B.-X. Wang, Optimisation of continuous casting process parameters based on coupled heat and stress model, Ironmaking & Steelmaking. 37(2) (2010) 147-154.
5. N. Zong, H. Zhang, Y. Liu, Z. Lu, Analysis on morphology and stress concentration in continuous casting bloom to learn the formation and propagation of internal cracks induced by soft reduction technology, Ironmaking & Steelmaking. 46(9) (2019) 872-885.