Journal of Materials Science

, Volume 28, Issue 19, pp 5169–5175 | Cite as

The effect of alloying elements on the structure and mechanical properties of ultra low carbon bainitic steels

  • Shyi -Chin Wang
  • Po -We Kao


Microalloying with Nb and B leads to a granular bainite microstructure which is composed of a bainitic ferrite matrix and a uniformly distributed martensite/austenite-constituent in the as-rolled condition. Due to this transformation strengthening mechanism, high strength and toughness could be achieved even though the C content was extremely low. It was found that both dissolved Nb in austenite and free B are prerequisites for granular bainite formation. Furthermore, there is a critical B content to achieve the complete bainitic transformation strengthening effect. The critical B content increases with C content. C thus diminishes the effect of B in promoting bainite transformation, due to the formation of boron carbides or the depletion of dissolved Nb in austenite. The effect of Mn, Mo and Ni on the decomposition of austenite is similar. A parameter“Mneq” which relates the effect of these alloying elements on the Bs temperature was derived. It was confirmed that the strength of bainitic steels is inversely proportional to theBs temperature.


Ferrite Austenite Boron Bainite Boron Carbide 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Chapman & Hall 1993

Authors and Affiliations

  • Shyi -Chin Wang
    • 1
  • Po -We Kao
    • 1
  1. 1.Institute of Materials Science and EngineeringNational Sun Yat-Sen UniversityKaohsiungTaiwan

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