Advertisement

Journal of Materials Science

, Volume 30, Issue 13, pp 3531–3538 | Cite as

Microstructure-fracture toughness correlation in weld joints of Cr-Mo steel

  • A. N. Kumar
  • R. K. Pandey
  • P. Sundaram
Article

Abstract

The strength-toughness-microstructure relationship in relation to the micromechanics of a fracture process has been investigated in the weld joints of two alloys: 0.5 Mo and 2.25 Cr-1 Mo steels. These alloys are extensively used to fabricate super-heater tubes, boilers, piping, gas lines, etc., by welding. The applications require high temperature and pressure to be maintained during service. The crack initiation toughness and tearing resistance were evaluated using crack tip opening displacement/J-integral parameters at different temperatures. Quantitative analysis of micro-structure and fracture surfaces was used to study the micromechanics of fracture process in the heat-affected zone (HAZ) of the alloys. Molybdenum steel exhibited a higher percentage of ferrite and lower martensite content, while the other steel showed aligned carbide as the major constituent. The higher hardness and strength values in the HAZ and welding zone (WZ) of Cr-Mo steel, compared to molybdenum steel, may be attributed to the higher amount of martensite phase in the alloy. The higher initiation toughness at 200° C in both the alloys was reflected in the larger dimple size, compared to the size observed at room temperature. A tendency for void sheet formation was noticed in both alloys. Acicular ferrite and martensite appeared to be the most influential constituents affecting tearing resistance and initiation toughness.

Keywords

Ferrite Martensite Weld Joint Acicular Ferrite Initiation Toughness 
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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    R. E. RAI, P. SUNDARAM, R. K. PANDEY, A. N. KUMAR, S. K. BANERJEE and S. K. GHOSH, Eng. Fract. Mech. 37 (1990) 163.CrossRefGoogle Scholar
  2. 2.
    V. R. RANGANATH, A. N. KUMAR and R. K. PANDEY, Mater. Sci. Eng. A132 (1991) 152.Google Scholar
  3. 3.
    P. SUNDARAM, PhD thesis, Indian Institute of Technology, Delhi (1989).Google Scholar
  4. 4.
    P. SUNDARAM, R. K. PANDEY and A. N. KUMAR, Mater. Sci. Eng. 91 (1987) 29.CrossRefGoogle Scholar
  5. 5.
    “Annual Book of ASTM Standards”, Part 31 (American Society for Testing and Materials, Philadelphia, PA, 1973) p. 960.Google Scholar
  6. 6.
    British Standards Institution Document, BS5762, “Methods for COD Testing” (BSI, 1979).Google Scholar
  7. 7.
    “Standard Test for JIc: A Measure of Fracture Toughness”, ASME E-813-81 (ASME, 1981).Google Scholar
  8. 8.
    D. J. ABSON and R. E. DOLBY, “A Schematic for the Quantitative Description of Ferritic weld Metal”, Report DCC IXJ29-80 (Welding Institute, UK, 1980).Google Scholar
  9. 9.
    S. HOEKSTRA, Met. Construct. 18 (1986) 771.Google Scholar
  10. 10.
    S. K. CHAUDHARI and V. RAMASWAMY, in “Proceedings of ICF5”, France (Pergamon Press, 1981) p. 1209.Google Scholar
  11. 11.
    C. L. CHOI and D. L. HILL, Weld. J. 57 (1978) 232.Google Scholar
  12. 12.
    H. G. PISARSKI and R. J. PARGETER, in “Proceedings of the International Conference on Welding in Energy Related Projects” (1983) pp. 415–28.Google Scholar
  13. 13.
    C. THAULOW, Met. Const. 17 (1985) 94.Google Scholar
  14. 14.
    K. ERIKSSON, in “Proceedings of ICFS”, France (Pergamon Press, 1981) p. 715.Google Scholar

Copyright information

© Chapman & Hall 1995

Authors and Affiliations

  • A. N. Kumar
    • 1
  • R. K. Pandey
    • 1
  • P. Sundaram
    • 1
  1. 1.Applied Mechanics DepartmentIndian Institute of Technology DelhiNew DelhiIndia

Personalised recommendations