Strength of Materials

, Volume 50, Issue 1, pp 176–183 | Cite as

Study on the Cracking Mechanism of YQ450NQR1 High-Strength Weathering Steel

  • J. S. Qing
  • X. D. Duan
  • M. F. Xiao
  • J. Q. Li
  • M. Liu
  • Q. Liu
  • H. F. Shen

YQ450NQR1 high-strength weathering steel is prone to cracking. The cracking patterns and morphology were detected by metallographic and scanning electron microscopies. The decarburized layer around the cracks is indicative of their origination in the continuous casting bloom. Then, the controlling factors were established by analyzing the carbon content of molten steel, residual elements in the alloy, purity and performance of the mold powder, and secondary cooling water flow of the mold. Results show that the process optimization reduced the cracking reject ratio from 3.5 to 0.78%.


high-strength weathering steel cracking decarburization layer 


  1. 1.
    J. S. Qing, H. F. Shen, and M. Liu, “V-N microalloying of high strength weathering steel YQ450NQR1,” Iron Steel, 52, No. 5, 87–93 (2017).Google Scholar
  2. 2.
    J. S. Qing, L. Wang, K. Dou, et al., “Influence of V–N microalloying on the high-temperature mechanical behavior and net crack defect of high strength weathering steel,” High Temp. Mater. Proc., 35, No. 6, 575–582 (2016).Google Scholar
  3. 3.
    D. Chen, L. Song, Z. Dong, et al., “Effect of cooling rate on high temperature mechanical properties of weathering steel,” J. Chongqing Univ., 34, No. 11, 50–55 (2011).Google Scholar
  4. 4.
    L. Liu and Z. Li, “Cracking analysis of 310 Z shape steel,” Phys. Test., 29, No. 1, 34–36 (2011).Google Scholar
  5. 5.
    M. Zhang, X. Zhao, Y. Zhu, et al., “Hot ductility of low carbon Nb-microalloyed weathering steel,” Adv. Mater. Res., 887–888, 200–206 (2014).Google Scholar
  6. 6.
    X. Wu, Y. Wan, Z. Zhang, et al., “Research on cracking sensitivity of weathering steel SMA490BW,” in: Proc. of the 2014 Int. Conf. on Mechatronics, Control and Electronic Engineering: Advances in Intelligent Systems Research, 113, 372–375 (2014).Google Scholar
  7. 7.
    S. Luo, Study and Application of Casting Solidification and Heat Transfer Model of 360 mm × 450 mm Continuous Casting Billet’s Online [in Chinese], Northeastern University (2008).Google Scholar
  8. 8.
    J. Qu and Z. Wang, “Prediction model of controlled rolling and controlled cooling in the austenitic phase transformation behavior,” J. Iron Steel Res., 10, No. 5, 41–43 (1998).Google Scholar
  9. 9.
    B. Mintz, “The influence of composition on the hot ductility of steels and to the problem of transverse cracking,” ISIJ Int., 39, No. 9, 833–855 (1999).CrossRefGoogle Scholar
  10. 10.
    G. Cardoso, B. Mintz, and S. Yue, “Hot ductility of aluminium and titanium containing steels with and without cyclic temperature oscillations,” Ironmak. Steelmak., 22, No. 5, 365–377 (1995).Google Scholar
  11. 11.
    X. Wang, W. Wang, and X. Liu, “Research on reducing the Nb, V, Ti microalloyed steel cc slab corner transverse cracks,” Iron Steel, 33, No. 1, 22–25 (1998).Google Scholar
  12. 12.
    L. Li and H. Gong, “Production practice of steel YQ450NQR1 steel for railway vehicles,” in: Proc. of the Fourteenth National Conference on Steelmaking (2006).Google Scholar
  13. 13.
    B. Mintz, “Importance of Ar3 temperature in controlling ductility and width of hot ductility trough in steels, and its relationship to transverse cracking,” Mater. Sci. Tech., 12, No. 2, 132–138 (1996).CrossRefGoogle Scholar
  14. 14.
    H. Kobayashi, “Hot-ductility recovery by manganese sulphide precipitation in low manganese mild steel,” ISIJ Int., 31, No. 3, 268–277 (1991).CrossRefGoogle Scholar
  15. 15.
    D. N. Crowther, Z. Mohamed, and B. Mintz, “Influence of micro-alloying additions on the hot ductility of steels heated directly to the test temperature,” Trans. Iron Steel I. Jpn., 27, No. 5, 366–375 (1987).CrossRefGoogle Scholar
  16. 16.
    K. Cai and Y. Zhang, “The high temperature mechanical properties of cast steel album,” J. Univ. Sci. Technol. B., 15, No. 2, 3–20 (1993).Google Scholar
  17. 17.
    Y. Kang and J. Han, Process Principle and Control Solid Forming [in Chinese], National Defense Industry Press, Beijing (2002).Google Scholar
  18. 18.
    K. Dou, J. S. Qing, L. Wang, et al., “Research on internal crack susceptibility of continuous-casting bloom based on micro-segregation model,” Acta Metall. Sin., 50, No. 12, 1505–1512 (2014).Google Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  • J. S. Qing
    • 1
  • X. D. Duan
    • 2
  • M. F. Xiao
    • 2
  • J. Q. Li
    • 2
  • M. Liu
    • 2
  • Q. Liu
    • 3
  • H. F. Shen
    • 1
  1. 1.Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, School of Materials Science and EngineeringTsinghua UniversityBeijingChina
  2. 2.Pansteel Group Co. Ltd.PanzhihuaChina
  3. 3.State Key Laboratory of Advanced MetallurgyUniversity of Science and TechnologyBeijingChina

Personalised recommendations