Microstructure and properties of Ti and Ti+Nb ultra-low-carbon bake hardened steels

  • Ji-ping ChenEmail author
  • Yong-lin Kang
  • Ying-min Hao
  • Guang-ming Liu
  • Ai-ming Xiong


Hot rolling, cold rolling and continuous annealing processes of Ti bearing and Ti+Nb stabilized ultra-low-carbon bake hardened steels were experimentally studied. The microstructure and texture evolution, as well as the morphology, size and distribution of second phase precipitates during hot rolling, cold rolling and continuous annealing were also analyzed. The results showed that the size of NbC precipitates in Ti + Nb stabilized ultra-low-carbon bake hardened steel was smaller than that of TiC precipitates in Ti bearing ultra-low-carbon bake hardened steel, which made the average grain size of Ti + Nb stabilized ultra-low-carbon bake hardened steel finer than that of Ti bearing ultra-low-carbon bake hardened steel: for the yield strength, the former was higher than the latter; but for the r value which reflects the deep-drawing performance, the former was lower than the latter.

Key words

ultra-low-carbon bake hardened steel texture microstructure mechanical property 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. [1]
    KANG Yong-lin. Quality Control and Formability of Modern Automobile Steel Sheet [M]. Beijing: Metallurgical Industrial Publishing Company, 1999 (in Chinese).Google Scholar
  2. [2]
    Kozeschnik E, Pletenev V, Zolotorevsky N, et al. Aluminum Nitride Precipitation and Texture Development in Batch-Annealed Bake-Hardening Steel [J]. Metall Mater Trans, 1999, 30A: 1663.CrossRefGoogle Scholar
  3. [3]
    Ooi S W, Fourlaris G, A Comparative Study of Precipitation Effects in Ti Only and Ti-V Ultra Low Carbon (ULC) Strip Steels [J]. Mater Charact, 2006, 56: 214.CrossRefGoogle Scholar
  4. [4]
    Berbenni S, Favier V, Lemoine X, et al. A Micromechanical Approach to Model the Bake Hardening Effect for Low Carbon Steels [J]. Scripta Mater, 2004, 51: 303.CrossRefGoogle Scholar
  5. [5]
    Zhao J Z, De A K, Cooman BCD. A Model for the Cottrell Atmosphere Formation During Aging of Ultra Low Carbon Bake Hardening Steels [J]. ISIJ Int, 2000, 40(7): 725.CrossRefGoogle Scholar
  6. [6]
    Zhao J Z, De A K, Cooman B C D. Formation of the Cottrell Atmosphere During Strain Aging of Bake-Hardenable Steels [J]. Metall Mater Trans, 2001, 32A: 417.CrossRefGoogle Scholar
  7. [7]
    Soenen B, De A K, Vandeputte S, et al. Competition Between Grain Boundary Segregation and Cottrell Atmosphere Formation During Static Strain Aging in Ultra Low Carbon Bake Hardening Steels [J]. Acta Mater, 2004, 52: 3483.CrossRefGoogle Scholar
  8. [8]
    Kvackaj T, Mamuzic I. Development of Bake Hardening Effect by Plastic Deformation and Annealing Conditions [J]. Metalurgija, 2006, 45(1): 51.Google Scholar
  9. [9]
    Jeong W C. Relationship Between Mechanical Properties and Microstructure in a 1.5%Mn-0.3%Mo Ultra-Low Carbon Steel With Bake Hardening [J]. Mater Lett, 2007, 61: 2579.CrossRefGoogle Scholar
  10. [10]
    Nie W J, Yang S W, Yuan S Q, et al. Dissolving of Nb and Ti Carbonitride Precipitates in Microalloyed Steels [J]. Journal of University of Science and Technology Beijing, 2003, 10 (5): 78.Google Scholar
  11. [11]
    Shalfan W A, Speer J G, Findley K, et al. Effect of Annealing Time on Solute Carbon in Ultra-Low-Carbon Ti-V and Ti-Nb Steels [J]. Metall Mater Trans, 2006, 37A: 207.CrossRefGoogle Scholar
  12. [12]
    Bocos J L, Novillo E, Petite M M, et al. Aspects of Orientation-Dependent Grain Growth in Extra-Low Carbon and Interstitial-Free Steels During Continuous Annealing [J]. Metall Mater Trans, 2003, 34A: 827.CrossRefGoogle Scholar

Copyright information

© China Iron and Steel Research Institute Group 2009

Authors and Affiliations

  • Ji-ping Chen
    • 1
    Email author
  • Yong-lin Kang
    • 1
  • Ying-min Hao
    • 1
  • Guang-ming Liu
    • 1
    • 2
  • Ai-ming Xiong
    • 2
  1. 1.School of Materials Science and EngineeringUniversity of Science and Technology Beijing, State Key Laboratory for Advanced Metals and MaterialsBeijingChina
  2. 2.Shougang Research Institute of TechnologyBeijingChina

Personalised recommendations