Effect of Different Cooling Rates on Microstructure and Property of Continuous Annealing IF Steel

Abstract:

The influence of different annealing cooling rates on microstructure,precipitation of the second phase and mechanical properties of IF steel was studied. The recrystallizing behavior of IF steels was analyzed by batch annealing process. After confirming the recrystallizing temperature of IF steel, the simulations of different continuous annealing cooling rates (5°C/s, 20°C/s, 50°C/s, 200°C/s 500°C/s and 1000°C/s ) were performed. At the same time, combined with TEM and XRD, the precipitating behavior and microstructure texture were analyzed. The results showed that the recrystallization temperature was speculated between 540°C and 560°C. As the cooling rate increased, the grain sizes became smaller and the yield strength increased significantly. And the tensile strength and elongation were more or less static. The tensile strength remained 240MPa and the elongation kept around 50%. With 1000°C/s cooling rate, the sample performed best with the r-value of 3.03. TiN precipitation was observed. The annealed texture is mostly composed of {111} texture.

• Periodical: Materials Science Forum (Volume 850)
• Pages: 631-635
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.850.631
• Online since: March 2016
• Authors: Ru Wen Zheng, Ren Bo Song, Wu Yan Fan, Wei Wang, Ke Guo, Zhong Hong Wang
• Keywords: Continuous Annealing, Interstitial-Free Steel, Second-Phase Precipitations, Texture

References

[1] P. Ghosh, R.K. Ray, C. Ghosh, D. Bhattacharjee, Comparative study of precipitation behavior and texture formation in continuously annealed Ti and Ti+Nb added interstitial-free high-strength steels, Scripta. 58(2008) 939-942.

DOI: 10.1016/j.scriptamat.2008.01.056

[2] P. Ghosh, B. Bhattacharya, and R.K. Ray, Comparative study of precipitation behavior and texture formation in cold rolled-batch annealed and cold rolled-continuous annealed interstitial free high strength steels, Scipta. 56(2007) 657-660.

DOI: 10.1016/j.scriptamat.2006.12.044

[3] Anmin Yin, Zhisong Cheng, Haitao Jiang, Study on evolution of recrystallization textures in Ti-IF steel during annealing, Material and Heat Treatment. 24(2009) 12-16.

[4] Cainian Jing, Zuocheng Wang, Futao Han, The second-phase particles in interstitial-free steels, Materials Review. 19(2005) 50-53.

[5] Renbo Song, Jingjing Du, Fuqiang Yang, Study on batch annealing process of thin specification cold-rolled IF steel, Hot Working Technology. 42(2013) 228-232.

[6] Guibin Cui, Xinhua Ju, Zeyang Wang, Influence of annealing temperature on microstructure and texture in IF steel, Transactions of Materials and Heat Treatment. 33(2012)136-141.

[7] Chunlian Yan, Guibin Cui, Xinhua Ju, Peng Guo, Yang Meng, Research on precipitates of Ti-IF and Ti+Nb+P-IF steels, Journal of Chinese Electron Microscopy Society. 31(2012) 124-128.

[8] Zisu Zhao, Weimin Mao, Yongning Yu, Precipitation behavior of FeTiP phase in high strength IF steel, Journal of University of Science and Technology Beijing. 7(2000) 197-203.