Microalloying design for microstructure refinement in hot rolled H-beam steels based on specifications
XING Jun1,2, ZHU Guo-hui1, DING Han-lin3, PU Chun-lei4, WANG Yong-qiang1, LIU Shu-lan5
1. School of Metallurgy Engineering, Anhui University of Technology, Maanshan 243002, Anhui, China; 2. Technology Center, Maanshan Iron and Steel Co., Ltd., Maanshan 243000, Anhui, China; 3. School of Iron and Steel, Soochow University, Suzhou 215006, Jiangsu, China; 4. Intelligent Development Department, MCC Huatian Engineering and Technology Corporation, Nanjing 210019, Jiangsu, China; 5. College of Physical Science and Technology, Tangshan Normal University, Tangshan 063000, Hebei, China
Abstract：Due to the limited reduction during the hot rolling of heavy hot-rolled H beam, the conventional method such as "strain induced transformation" can′t be applied to achieve the microstructure refinement of heavy hot-rolled H-beam. A new method by means of the abundant austenite grain boundaries providing the nucleation sites for ferrite transformation has been proposed, in which a reasonable microalloying is necessary to be considered. The theoretical analysis shows that the refinement of austenite grains before the finish rolling contributes to reducing the critical strain for austenite dynamic recrystallization and then stimulating the occurrence of dynamic recrystallization. Therefore, how to restrain the austenite grain growth during the rough rolling by use of the second phase particles existed stably at high temperatures becomes one of the key issues to be considered during the microalloying of heavy hot-rolled H beam. The experimental results show that the Ti/N microalloying is conducive to the grain refinement of heavy hot-rolled H-beam due to the inhibition of the grain growth during the reheating and rough rolling. Furthermore, NbC particles tend to be precipitated epitaxially attaching to TiN particles, resulting in the more fined and dispersed distribution, which is beneficial to suppress the static recrystallization during passes and then improve the strength and toughness of heavy hot-rolled H-beam.
邢军, 朱国辉, 丁汉林, 蒲春雷, 王永强, 刘淑兰. 面向不同规格热轧H型钢组织细化的微合金化设计[J]. 钢铁, 2023, 58(3): 144-150.
XING Jun, ZHU Guo-hui, DING Han-lin, PU Chun-lei, WANG Yong-qiang, LIU Shu-lan. Microalloying design for microstructure refinement in hot rolled H-beam steels based on specifications[J]. Iron and Steel, 2023, 58(3): 144-150.
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2023, Vol. 58 
