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Metal Science and Heat Treatment

, Volume 20, Issue 7, pp 584–594 | Cite as

Effect of the quantity of nonmartensitic transformation products on the resistance to fracture of quenched and tempered structural steels

  • A. P. Gulyaev
  • Yu. S. Golovanenko
  • V. N. Zikeev
Scientific-Technical Information
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Conclusions

  1. 1.

    After tempering to the same hardness (HV 300) the presence of nonmartensitic structures in the quenched steels has practically no effect on the standard mechanical properties (σb, σ0.2, δ, ψ) of quenched and tempered structural steels; there is a difference in the effect of these structures on the characteristics of resistance to fracture.

     
  2. 2.

    The even distribution of finely dispersed carbide phase in lower bainite after tempering increases the resistance to brittle fracture.

     
  3. 3.

    Upper bainite in quenched steels 18KhNMFA and 42KhMFA leads after tempering to the formation of large uneven branched carbide inclusions, which raises the ductile-brittle transition temperature and reduces the work of crack propagation.

     
  4. 4.

    The presence of austenite decomposition products in the upper range of critical temperatures, i.e., the ferritic-pearlitic component in structural steels quenched to martensite and bainite, leads to a reduction of the resistance to brittle fracture.

     
  5. 5.

    Structural steels hardened with continuous cooling may contain 50% lower bainite along with martensite, which does not impair the properties. This makes it possible to increase the critical section of machine parts, reduce the cooling capacity of the quenching medium, or use a less alloyed steel for the given application.

     

Keywords

Carbide Austenite Martensite Critical Temperature Bainite 
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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Literature cited

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Copyright information

© Plenum Publishing Corporation 1979

Authors and Affiliations

  • A. P. Gulyaev
  • Yu. S. Golovanenko
  • V. N. Zikeev

There are no affiliations available

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