Journal of Materials Science

, Volume 29, Issue 6, pp 1612–1616 | Cite as

Effect of continuous-cooling transformation structure on mechanical properties of 0.4C-Cr-Mo-Ni steel

  • Yoshiyuki Tomita


Commercially available 0.4C-Cr-Mo-Ni steel was studied to determine the effects on its mechanical properties of various microstructures produced by continuous-cooling transformation after austenitization. A good combination of strength and notch toughness was obtained independently of test temperatures (293 and 193 K) when the steel was austenitized at 1173 K and then continuously cooled at an average rate of ∼ 3.1 K s−1 (expressed as the average cooling rate from 823 to 573 K) before final rapid cooling. The microstructure of the steel consisted of a mixed structure of martensite and 10–15 vol% lower bainite, which appeared in acicular form in association with the martensite. Slower cooling had a detrimental effect on the mechanical properties of the steel; the microstructure of this steel consisted of a mixed structure of martensite and upper bainite, which appeared as masses in the matrix. As the average cooling rate increased, the lath size and internal stringer-carbide size in the upper bainite were larger, and retained a somewhat increased austenite content.


Microstructure Mechanical Property Austenite Martensite Average Rate 
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Copyright information

© Chapman & Hall 1994

Authors and Affiliations

  • Yoshiyuki Tomita
    • 1
  1. 1.Department of Metallurgy and Materials ScienceUniversity of Osaka PrefectureOsakaJapan

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