CCT curves of low-carbon Mn-Si steels and development of water-cooled bainitic steels

  • Feng-yun XuEmail author
  • Yong-wei Wang
  • Bing-zhe Bai
  • Hong-sheng Fang


CCT curves of Mn-Si steels with different manganese contents or carbon contents were determined. The results show that the transformation range of bainite can be separated from that of ferrite when the manganese content approaches a certain content, and the incubation period of ferrite increases more significantly than that of bainite transformation with the increase of carbon content in Mn-Si steels. Furthermore, water-cooled bainitic steels without adding expensive alloying element were developed. Granular bainite was obtained when a bar with diameter of 300 mm was cooled by water, and a mixed microstructure of granular bainite and martensite was obtained in water-cooled plate with thickness of 40 mm. The developed water-cooled bainitic steels containing no expensive alloying element showed a good combination of strength and toughness. The tensile strength, yield strength, and toughness (AKU at −20 °C ) of bar with diameter of 300 mm after water cooling were higher than 850 MPa, 620 MPa, and 65 J, respectively, and those of plate with thickness of 40 mm after water cooling were higher than 1000 MPa, 800 MPa, and 50J, respectively.

Key words

bainitic steel water cooling granular bainite CCT curve Mn-Si steel 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. [1]
    FANG Hong-sheng. Novel Hot Rolling Bainitic Steel-Low Carbon Mn-B Series Engineering Steels 12Mn-B and 16Mn-B [J]. Metallic Materials Research, 1976. 4(12): 913.Google Scholar
  2. [2]
    YANG Liu, FANG Hong-sheng, MENG Zhi-he. Kinetics of Austenitic Isothermal Decomposition and Mn Partition in Fe-C-Mn-B Alloys [J]. Acta Metall Sin, 1992, 28(1): A16 (in Chinese).Google Scholar
  3. [3]
    FANG Hong-sheng, FENG Chun, ZHENG Yan-kang, et al. Creation and Development of Novel Mn Series Air Cooled Bainitic Steels [J]. Heat Treatment, 2008, 23(3): 2 (in Chinese).Google Scholar
  4. [4]
    YANG Zhigang, FANG Hong-sheng, WANG Jia-jun, et al. Study of the Novel Carbon Mn-B Bainitic Steel Auto Connecting Rod and Freight Fork [J]. Mater Mech Eng, 1993, 17(6), 18 (in Chinese).Google Scholar
  5. [5]
    FANG Hong-sheng, LIU Dong-yun, CHANG Kao-di, et al. Microstructure and Properties of 1500MPa Economical Bainite/Martensite Duplex Phase Steel [J]. J Iron Steel Res, 2001, 13(3): 31 (in Chinese).Google Scholar
  6. [6]
    HUANG Wei-gang, FANG Hong-sheng, ZHENG Yan-kang. Effect of Silicon Content on the Microstructure and Properties in Mn-B Air-Cooled Bainitic Steel [J]. Trans Met Heat Treat, 1997, 18(1): 8 (in Chinese).Google Scholar
  7. [7]
    ZHANG Ming-xing, KANG Mo-kuang. Influence of Si on Microstructure and Properties of Low Carbon Bainitic Steels [J]. Acta Metall Sin, 1993, 29(1): A6 (in Chinese).MathSciNetGoogle Scholar
  8. [8]
    LIU Shi-kai, YANG Liu, ZHANG Jun, et al. Influence of Si and Mn on Morphology of Bainitic Ferrite and Kinetics of Bainhe Transformation in Fe-C alloy [J]. Acta Metall Sin, 1992, 28(12): A513 (in Chinese).Google Scholar
  9. [9]
    WANG Feng-xiang, JIAN Fang, FENG Yan. Determination of CCT Curves of 27SiMn Steel [J]. Science and Technology of Baotou Steel (Group) Corporation, 2007, 33(2): 26 (in Chinese).Google Scholar
  10. [10]
    XIAO Gui-zhi, DI Hong-shuang, JIA Xue-Jun. Effect of Heat Treatment on Mechanical Properties of 30MnSi PC Steel Bar [J]. Iron and Steel, 2007, 42(4): 73 (in Chinese).Google Scholar
  11. [11]
    FENG Yan, WANG Feng-xiang, JIAN Fang. Experimental Study of Evolution Law of Microstructure of Hydraulic Pillar-Used 27SiMn Steel Seamless Tubes [J]. Science and Technology of Baotou Steel (Group) Corporation, 2006, 32(1): 31 (in Chinese).Google Scholar
  12. [12]
    LI An-ming. Effect of Autenitizing Temperature and Time on Microstructure and Property of Steel 27SiMn [J]. Heat Treatment of Metals, 2003, 28(9): 39 (in Chinese).Google Scholar

Copyright information

© China Iron and Steel Research Institute Group 2010

Authors and Affiliations

  • Feng-yun Xu
    • 1
    Email author
  • Yong-wei Wang
    • 1
  • Bing-zhe Bai
    • 1
  • Hong-sheng Fang
    • 1
  1. 1.Key Laboratory for Advanced Materials of Ministry of Education, Department of Materials Science and EngineeringTsinghua UniversityBeijingChina

Personalised recommendations