Grain refinement of low carbon steel produced by CSP process

Xiangdong Huo, Delu Liu, Yuanli Wang, Nanjing Chen, Yonglin Kang, and Jie FuMaterials Science and Engineering School, University of Science and Technology Beijing, 100083 Beijing, ChinaMetallurgical and Ecological Engineering School, University of Science and Technology Beijing, 100083 Beijing, China

摘 要：<正> In comparison with conventional production for hot strips, compact strip production （CSP） brings about some new micro-structural phenomena. Investigations were carried out to clarify the grain refinement mechanism of low carbon steel strips produced by the EAF-CSP process. Samples, obtained from the same rolling stock during continuous rolling, were examined through SEM, TEM and XEDS. Thin slabs have a dominant columnar structure and the spacing of the secondary dendrite arms ranges from 90 to -125 μm. The average grain sizes for the central area of the samples from the 1st to 6th pass are 41.6, 25.2, 21.4, 20.2, 13.1, 6.7 μm, respectively. Large number of nanometer oxide and sulfide have been found in the low carbon steel produced by the CSP process. The grain refinement mechanism can be summarized as follows: finer solidification structure of the thin slab; austenite recrystalliza-tion at higher temperature and stain accumulation at lower temperature caused by the great reduction of single rolling p

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