Effect of isothermal transformation temperature on the microstructure, precipitation behavior, and mechanical properties of anti-seismic rebar
Author:
Zhang Junxiang1, Gu Shangjun2, Wang Jie2, Wei Fulong2, Li Zhiying1, Zeng Zeyun1, Shen Bin1, Li Changrong13
Affiliation:
1. College of Materials and Metallurgy, Guizhou University , Guiyang , Guizhou, 550025 , China 2. Shougang Shuicheng Iron and Steel (Group) Co., Ltd , Liupanshui , 553000 , China 3. Province Key Laboratory of Metallurgical and Process Energy Saving , Guiyang , Guizhou 550025 , China
Abstract
Abstract
The synergy between Nb/Ti strengthening and precise isothermal transformation temperatures has resulted in the optimal microstructure and mechanical properties in Nb/Ti anti-seismic rebars. The microstructure, precipitates, and mechanical properties of experimental steels at different isothermal transformation temperatures were characterized using scanning electron microscopy, transmission electron microscopy, electron backscatter diffraction, and universal tensile testing machine. As the isothermal transformation temperature decreased from 700 to 600°C, the ferrite grain size, pearlite interlamellar spacing, and carbon diffusion coefficient of the experimental steel decreased to 6.69 μm, 0.17 μm, and 0.14 cm2·s−1, respectively, while the yield strength and tensile strength increased to 584 and 714 MPa, respectively. At 600°C, the pearlite transformation rate in the experimental steel was the fastest, accompanied by the most rapid precipitation kinetics. The precipitates were (Nb, Ti)C of approximately 50 nm in size, with a mismatch of 14.24% at the matrix/precipitate interface and a screw dislocation angle of 2.07°. The presence of screw dislocation steps may facilitate nucleation of Nb/Ti precipitates, forming semi-coherent interfaces.
Publisher
Walter de Gruyter GmbH
Reference58 articles.
1. Huang, S., C. Li, Z. Li, Z. Zeng, Y. Zhai, and J. Wang. Quantitative analysis of microstructure and mechanical properties of Nb–V microalloyed high-strength seismic reinforcement with different Nb additions. High Temperature Materials and Processes, Vol. 40, 2021, pp. 300–309. 2. Weng, Y. Q. Ultra-fine grain steel-theory and control techniques for the refinement of steel microstructure, Metallurgical Industry Press, Beijing, 2003. 3. GB/T 1499.2–2018 Steel for the reinforcement of concrete-Part 2: Hot rolled ribbed bars, 2018. 4. Yong, Q. L., Z. Y. Zhang, X. J. Sun, J. C. Cao, and Z. D. Li. Effect of dissolved niobium on eutectoid transformation behavior. Journal of Iron and Steel Research, International, Vol. 24, 2017, pp. 973–978. 5. Hu, G. X., X. Cai, and Y. H. Rong. Fundamental of materials science, Shanghai Jiaotong University Press, Shanghai, 2010.
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