Low-temperature fracture toughness of a heat-treated mild steel

  • C. C. Chama


Specimens from a 0.14 % C mild steel were austenitized at 1000 °C for 1 h and thereafter furnace-cooled or isothermally transformed at 700 °C for 0.5,2, and 8 h. The microconstituents present in the as-received material were ferrite and pearlite and their amounts did not substantially change even after heat treatment. The impact energy of the as-received and the furnace-cooled materials increased from 4 to 89 J and from 4 to 108 J, respectively, when the temperature was changed from - 196 to 23 °C. For these materials, the failure mode was by ductile fracture at 0 and 23 °C and by quasicleavage fracture at - 196 and - 40 °C. The fracture toughness did not show any significant change with isothermal transformation time at 700 °C. The failure mode of the isothermally transformed materials was always by quasicleavage fracture.


fracture toughness heat-treated mild steels low-temperature fracture transition fracture modes 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    J. Yu and C.J. McMahon, Jr., Variation of the Fracture Mode in Temper Embrittled 2.25 Cr-1 Mo Steel,Metall. Trans., Vol 16A, 1985, p1325–1331CrossRefGoogle Scholar
  2. 2.
    E. Tschegg and S. Stanzl, Fatigue Crack Propagation and Threshold in b.c.c. and f.c.c. Metals at 77 and 293 K,Acta Metall., Vol 29, 1981, p 33–40CrossRefGoogle Scholar
  3. 3.
    T.M. Maccagno and J.F. Knott, The Low Temperature Brittle Fracture Behaviour of Steel in Mixed Modes I and II,Eng. Fract. Mech.,Vol 38, 1991, p 111–128CrossRefGoogle Scholar
  4. 4.
    X. Yan and W. Lei, Research into Fracture Behavior of Mild Steel in Crack-Like Notch Impact Test,Scripta Met. Mater., Vol 29, 1993, p 797–800CrossRefGoogle Scholar
  5. 5.
    A.R. Rosenfield and G.T. Hahn, Numerical Descriptions of the Ambient Low-Temperature, and High-Strain Rate Flow and Fracture Behavior of Plain Carbon Steel,Trans. ASM, Vol 59, 1966, p 962–980Google Scholar
  6. 6.
    D. A. Curry and J.F. Knott, Effects of Microstructure on Cleavage Fracture Stress in Steel,Met. Sci., Vol 12, 1978, p 511–514CrossRefGoogle Scholar
  7. 7.
    T. Lin, A.G. Evans, and R.O. Ritchie, Stochastic Modeling of the Independent Roles of Particle Size and Grain Size in Transgranular Cleavage Fracture,Metall. Trans., Vol 18A, 1987, p 641–651CrossRefGoogle Scholar
  8. 8.
    V. Tvergaard and A. Needleman, Effect of Material Rate Sensitivity on Failure Modes in the Charpy V-Notch Test,J. Mech. Phys. Solids, Vol 34, 1986, p 213–241CrossRefGoogle Scholar
  9. 9.
    R.W. Balluffi and L.L. Seigle, Growth of Voids in Metals during Diffusion and Creep,Acta Metall., Vol 5, 1957, p 449–454CrossRefGoogle Scholar
  10. 10.
    J.A. Brinkman, Mechanism of Pore Formation Associated with the Kirkendall Effect,Acta Metall., Vol 3, 1955, p 140–145CrossRefGoogle Scholar
  11. 11.
    R.W. Bauer and H.G.F. Wilsdorf, Void Initiation in Ductile Fracture,Scripta Metall., Vol 7,1973, p 1213–1220CrossRefGoogle Scholar
  12. 12.
    N.R. Moody and W.W. Gerberich, Fatigue Crack Propagation in Iron and Two Iron Binary Alloys at Low Temperatures,Mater. Sci. Eng., Vol 41, 1979, p 271–280CrossRefGoogle Scholar
  13. 13.
    F.B. Pickering and T. Gladman, “An Investigation into Some Factors Which Control the Strength of Carbon Steels,” Special Report 81, Iron and Steel Institute, 1963Google Scholar
  14. 14.
    A. Needleman and V. Tvergaard, A Numerical Study of Void Distribution Effects on Dynamic, Ductile Crack Growth,Eng. Fract. Mech., Vol 38,1991, p 157–173CrossRefGoogle Scholar
  15. 15.
    R. Becker, The Effect of Porosity Distribution on Ductile Failure,J. Mech. Phys. Solids, Vol 35,1987, p 577–599CrossRefGoogle Scholar
  16. 16.
    PR. Frise and R. Bell, Fatigue Crack Growth and Coalescence at Notches,Int. J. Fatigue, Vol 14,1992, p 51–56CrossRefGoogle Scholar
  17. 17.
    J.H. Chen and C. Yan, Fracture Behaviour of C-Mn Steel Multipass MMA Weld Metals at -60 °C in Charpy V Testing,Mater. Sci. Technol, Vol 4, 1988, p 732–739CrossRefGoogle Scholar
  18. 18.
    S. Danyluk and I. Wolke, Low Temperature Impact Properties of Phosphorus and Sulfur Doped and Sensitized Type 304 Stainless Steel,Metall. Trans., Vol 17A, 1986, p 663–668CrossRefGoogle Scholar
  19. 19.
    E. Molinié, R. Piques, and A. Pineau, Behaviour of a lCr-lMo-0.25V Steel after Long Term Exposure-I. Charpy Impact Toughness and Creep Properties,Fatigue Fract. Eng. Mater. Struct., Vol 14,1991, p 531–545CrossRefGoogle Scholar
  20. 20.
    P. Bowen, S.G. Druce, and J.F. Knott, Micromechanical Modelling of Fracture Toughness,Acta Metall, Vol 35, 1987, p 1735–1746CrossRefGoogle Scholar

Copyright information

© ASM International 1995

Authors and Affiliations

  • C. C. Chama
    • 1
  1. 1.Department of Metallurgy and Mineral ProcessingUniversity of ZambiaLusakaZambia

Personalised recommendations