Metal Science and Heat Treatment

, Volume 19, Issue 7, pp 512–517 | Cite as

Kinetics of crack growth in maraging and medium-alloy steels during low-cycle impact fatigue tests

  • I. V. Pestov
  • V. A. Ostapenko
  • M. D. Perkas
  • A. Ya. Maloletnev
  • N. A. Kretov
Maraging Steels

Conclusions

  1. 1.

    The duration of the period of crack nucleation in steels N18K9M5T and 30KhN2MFA varies little with the magnitude of cyclic stresses.

     
  2. 2.

    A period of slow crack growth is observed in steels 30KhN2MFA and N18K9M5T at σmax=165 kgf/mm2 and is characterized by fatigue microbands in the fracture-ductile in the maraging steel, brittle in the medium-carbon steel. With increasing crack length (period of accelerated crack growth) the area occupied by microbands in the fracture decreases and the percentage of dimpled fracture increases.

     
  3. 3.

    At high cyclic stresses (σmax=260 and 360 kgf/mm2) the period of slow crack growth is absent in steels 30KhN2MFA and N18K9M5T.

     
  4. 4.

    The rate of crack growth determined by the difference of electrical potentials is in satisfactory agreement with the width of fatigue microbands, particularly in the period of slow crack growth. In the period of accelerated crack growth it is somewhat higher than the width of microbands.

     
  5. 5.

    The high regularity of fatigue microbands in the fractures of steel N18K9M5T indicates greater evenness of the properties determining the resistance to fracture at high cyclic impact loads than for steel 30KhN·2MFA.

     

Keywords

Fatigue Cyclic Stress Crack Nucleation Maraging Steel Slow Crack Growth 
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

© Plenum Publishing Corporation 1977

Authors and Affiliations

  • I. V. Pestov
  • V. A. Ostapenko
  • M. D. Perkas
  • A. Ya. Maloletnev
  • N. A. Kretov

There are no affiliations available

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