Effect of Nb on the dynamic recrystallization behavior of high-grade pipeline steels

Tao Niu1,2), Yong-lin Kang1,2), Hong-wei Gu1,2), Yu-qun Yin3), Ming-liang Qiao3), and Jin-xing Jiang3) 1) School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China 2) State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 10083, China 3) Nanjing Iron and Steel Co. Ltd., Nanjing 210035, China

摘 要：The dynamic recrystallization （DRX） behavior of high-grade X80/X100 pipeline steels with different Nb contents was investi-gated through single pass compression experiment using a Gleeble 1500 thermomechanical simulator. By the regression of stress-strain data obtained in the experiment, the deformation activation energy of DRX was identified, and the critical strain was calculated with the Po-liak-Jonas （P-J） method. Based on the analysis, the occurrence condition and kinetics of DRX were determined. The results show that as the Nb content increases from 0.08wt% to 0.095wt%, the activation energy of recrystallization raises from 365 to 395 kJ/mol. The critical strain of DRX can be determined more accurately by the P-J method, and the ratios of critical strain to peak strain of X80 and X100 pipeline steels are 0.51 and 0.49, respectively, which are similar to the results achieved by other researchers and calculated with empirical formulae.

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