Reducing Shrinkage Porosity in High-Performance Steel Castings: Case of an ASME B16.34 Gate Valve Body: Part 1—Analysis, Techniques and Experimental Approach

Article
  • 5 Downloads

Abstract

X-ray computed tomography (CT), in combination with scanning electron microscopy (SEM), has been successfully used to evaluate shrinkage macro- and microporosity levels in a high-performance steel casting. As a test case, a commercially available gate valve body of a Class 300 gate valve based on the ASME B16.34 standard and made from A216 WCB cast steel was analysed, in accordance with the specifications of the standard. The radiographic inspection process, in accordance with ASTM E2868 for digital radiographs, is presented. Both X-ray CT radiographs and SEM micrographs are presented, showing the presence of shrinkage macro- and microporosity, in addition to gas porosity. This study is a precursor to the development of a systematic approach for reducing shrinkage porosity in castings based on the optimisation of design and process parameters that influence porosity formation during solidification.

Keywords

shrinkage porosity X-ray computed tomography scanning electron microscopy 

Notes

Acknowledgements

This research was supported by a Grant from the National Research Foundation (NRF) (Grant No. 105910), South Africa.

References

  1. 1.
    J. Campbell, Castings, 2nd edn. (Butterworth-Heinemann, Oxford, 2003)Google Scholar
  2. 2.
    P. Beeley, Foundry Technology, 2nd edn. (Butterworth-Heinemann, Oxford, 2001)Google Scholar
  3. 3.
    E. Niyama, T. Uchida, M. Morikawa, S. Saito, A method of shrinkage prediction and its application to steel casting practice. Int. Cast. Met. J. 7(3), 52–63 (1982)Google Scholar
  4. 4.
    K.D. Carlson, Z. Lin, R.A. Hardin, C. Beckermann, Modelling of Porosity Formation and Feeding Flow in Steel Casting, in 56th SFSA Technical and Operating Conference, Chicago, 2002Google Scholar
  5. 5.
    J.A. Dantzig, M. Rappaz, Solidification (EPFL Press, Lausanne, 2009)CrossRefGoogle Scholar
  6. 6.
    K.D. Carlson, C. Beckermann, Prediction of shrinkage pore volume fraction using dimensionless Niyama criterion. Metall. Mater. Trans. A 40, 163–175 (2009)CrossRefGoogle Scholar
  7. 7.
    C.A. Monroe, D.A. Gorsky, R.K. Huff, R.V. Grandhi, Improving the directional solidification of complex geometries through Taper addition. Int. J. Metalcast. 8, 23–27 (2014)CrossRefGoogle Scholar
  8. 8.
    R.A. Hardin, C. Beckermann, Effect of porosity on the stiffness of cast steel. Metall. Mater. Trans. A 8(12), 2992–3006 (2007)CrossRefGoogle Scholar
  9. 9.
    E. Ol’khovik, Study of the effect of shrinkage porosity on strength low carbon cast steel, in IOP Conf Ser-Mat Sci, 91(1), ISSN 1757-8981, 2015Google Scholar
  10. 10.
    K. Sigl, R.A. Hardin, R. Stephens, C. Beckermann, Fatigue of 8630 cast steel in the presence of porosity. Int. J. Cast. Metal. Res. 17(3), 130–146 (2004)CrossRefGoogle Scholar
  11. 11.
    M. El-Bealy, B.G. Thomas, Prediction of dendrite arm spacing for low alloy steel casting processes. Metall. Mater. Trans. B 27B, 689–692 (1996)CrossRefGoogle Scholar
  12. 12.
    K.D. Carlson, C. Beckermann, Use of the Niyama criterion to predict shrinkage-related leaks in high-nickel steel and nickel-based alloy castings, in 62nd SFSA Technical and Operating Conference, pp. 1–18, 2008Google Scholar
  13. 13.
    A. Du Plessis, P. Rossouw, X-ray computed tomography of a titanium aerospace investment casting. Case Stud. Nondestruct. Test. Eval. 3, 21–26 (2015)CrossRefGoogle Scholar
  14. 14.
    K. Kishitake, S. Matsuo, T. Okamoto, Microsegregation in low chromium steel castings. J. Iron Steel Inst. Jpn. 63(7), 1108–1115 (1977)CrossRefGoogle Scholar
  15. 15.
    ASME-B16.34: Valves—Flanged, Threaded and Welding End. American Society of Mechanical Engineers, New York, 2017Google Scholar
  16. 16.
    K. Carlson, S. Ou, R. Hardin, C. Beckerman, Analysis of ASTM X-ray shrinkage rating for steel castings. Int. J. Cast Metals Res. 14, 169–183 (2001)CrossRefGoogle Scholar
  17. 17.
    M. Blair, R. Monroe, R. Hardin, C. Beckerman, A new standard for radiographic acceptance criteria for steel castings, in Proceedings of the 62nd SFSA Technical and Operating Conference, Paper No. 5.5, Steel Founders’ Society of America, Chicago, 2008Google Scholar

Copyright information

© American Foundry Society 2018

Authors and Affiliations

  1. 1.Department of Mechanical and Mechatronic EngineeringStellenbosch UniversityStellenboschSouth Africa

Personalised recommendations