Advertisement

Metallurgical and Materials Transactions B

, Volume 50, Issue 1, pp 98–109 | Cite as

Surface Characteristics and Hardness Variations in Electrical Discharge Machining of Enhanced Nitrogen in Vanadium Steels

  • Nİhal EkmekcİEmail author
  • İsa Keskİn
Article
  • 76 Downloads

Abstract

Enhanced nitrogen in steels containing vanadium causes fine precipitates of vanadium nitride, which improve the hardenability properties. However, understanding the response of such steels to electrical discharge machining (EDM) is incomplete and needs further investigation. Therefore, EDM of enhanced nitrogen in steels containing vanadium was compared with a similar compositional steel that was free of nitrogen. The surface morphology, microstructural alterations, microhardness variation, and compositional depth profiling of the samples machined by EDM in oil and deionized water dielectric liquids were examined. Microscopic studies were carried out using optical and scanning electron microscopy. Phases were identified by X-ray diffractometry, and elemental depth profiling was performed using glow discharge optical emission spectroscopy. The hardness of the resolidified and heat-affected layers was measured using a Vickers type microhardness tester. The results of this study revealed that the dissolved nitrogen in steel decreased the probability of surface cracks and resulted in a softer resolidified layer structure when machining in the oil dielectric liquid. Thus, the presence of nitrogen reduced the formation of tension-induced martensite in the resolidified layer. Moreover, the heat-affected zone below the resolidified layer exhibited a uniform and harder structure, compared with the steel without nitrogen content, indicating the fast nature of the thermal cycles in EDM. The free nitrogen in steel did not dissociate during sparking; therefore, precipitation strengthening occurred in the heat-affected zone.

Notes

Acknowledgment

The authors acknowledge the funding by The Zonguldak Bülent Ecevit University Research Program. (Grant No. 2015-77654622-02.)

References

  1. 1.
    Stasko R, Adrian H, Adrian A: Mater Charact., 2006, vol. 56, pp. 340–347.CrossRefGoogle Scholar
  2. 2.
    Abbasi S M, Shokuhfar A: J Iron Steel Res Int., 2007, vol. 14, pp. 74–78.CrossRefGoogle Scholar
  3. 3.
    Yang C, Wang Q: J Iron Steel Res Int., 2008, vol. 15, pp. 81–86.CrossRefGoogle Scholar
  4. 4.
    Lv Y, Sheng G, Jiao Y: Constr Build Mater., 2014, vol. 69, pp. 18–25.CrossRefGoogle Scholar
  5. 5.
    Oksiuta Z, Lewandowska M, Kurzydlowski K J, Baluc N: J Nucl Mater., 2013, vol. 442, pp. S84–S88.CrossRefGoogle Scholar
  6. 6.
    Glodowski R J: Int J Metall Eng., 2013, vol. 2, pp. 56–61.Google Scholar
  7. 7.
    Mohammed R, Reddy G M, Rao K S: Defence Technol., 2015, vol. 11, pp. 237–243.CrossRefGoogle Scholar
  8. 8.
    Hojjatzadeh S M H, Halvaee A, Sohi M H: J. Mater. Process. Technol., 2012, vol. 212, pp. 2496–2504.CrossRefGoogle Scholar
  9. 9.
    Yurev AB, Godik LA, Kozyrev NA, Korneva LV, Tokarev AV: Steel Transl., 2008, vol. 38, pp. 756–758.CrossRefGoogle Scholar
  10. 10.
    Soni J S, Chakraverti G: J Mater Process Tech., 1996, vol. 56, pp. 439–451.CrossRefGoogle Scholar
  11. 11.
    Ekmekci B: Metall. Mater. Trans. B., 2009, vol. 40, pp. 70–81.CrossRefGoogle Scholar
  12. 12.
    Ekmekci B: Appl. Surf. Sci., 2007, vol. 253. pp. 9234–9240.CrossRefGoogle Scholar
  13. 13.
    Ekmekci B, Tekkaya A E, Erden A: Int J Mach Tool Manu., 2006, vol. 46, pp. 858–868.CrossRefGoogle Scholar
  14. 14.
    Lee H T, Tai T Y: J Mater Process Tech., 2003, vol. 142, pp. 676–683.CrossRefGoogle Scholar
  15. 15.
    Guu Y H, Hou M T: Mater Sci Eng A., 2007, vol. 466, pp. 61–67.CrossRefGoogle Scholar
  16. 16.
    Santos R F, Silva E R, Sales W F, Raslan A A: Proc. CIRP, 2016, vol. 45, pp. 303–306.CrossRefGoogle Scholar
  17. 17.
    Assarzadeh S., Ghoreishi M: J. Manuf. Process, 2017, vol. 30, pp. 502–515.CrossRefGoogle Scholar
  18. 18.
    Buschaiah K, JagadeeswaraRao M, Krishnaiah A: Mater. Today: Proceedings, 2018, vol. 5, pp. 3648–3656.CrossRefGoogle Scholar
  19. 19.
    Dwivedi A P, Choudhury S K: Mater. Today: Proceedings, 2017, vol. 4, pp. 10816–10822.CrossRefGoogle Scholar
  20. 20.
    Flaño O, Ayesta I, Izquierdo B, Sánchez J A, Ramos J M: Procedia CIRP, 2018, vol. 68, pp. 405–410.CrossRefGoogle Scholar
  21. 21.
    Zeilmann R P, Ivaninski T, Webber C: Procedia CIRP, 2018, vol. 71, pp. 472–477.CrossRefGoogle Scholar
  22. 22.
    Reddy G V P, Mariappan K, Kannan R, Sandhya R, Sankaran S, Rao K B S: Int J Fatigue, 2015, vol. 81, pp. 309–317.CrossRefGoogle Scholar
  23. 23.
    Kıyak M, Çakır O: J Mater Process Tech., 2017, vol. 191, pp. 141–144.CrossRefGoogle Scholar
  24. 24.
    Ekmekci B, Yaşar H, Ekmekci N: J. Manuf. Sci. Eng., 2016, vol. 138, pp. 081006–1–9.CrossRefGoogle Scholar

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2018

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringZonguldak Bülent Ecevit UniversityZonguldakTurkey
  2. 2.Graduate School of Natural and Applied SciencesZonguldak Bülent Ecevit UniversityZonguldakTurkey

Personalised recommendations