Skip to main content
Log in

Characterization of eutectic borides formed during solidification of borated stainless steel 304B4

  • Research Paper
  • Published:
Welding in the World Aims and scope Submit manuscript

Abstract

AISI 304B4 stainless steel (SS) containing 1.3 wt.% boron was cracking extensively during fabrication of neutron shields for Prototype Fast Breeder Reactor (PFBR). However, earlier study on 304B4 steel showed good resistance to weld solidification cracking due to eutectic backfilling in the cracks during welding. In order to understand the backfilling mechanism in this steel, microstructural characterization was performed on 304B4 SS in solution-annealed and re-melted and solidified conditions. In solution-annealed condition, microstructure of 304B4 SS consists of austenite matrix with random distribution of blocky Cr2B-type borides. On contrary, as-solidified microstructure reveals the primary austenite dendrites and interdendritic eutectic of (Fe,Cr)2B-type borides of varying morphologies. In addition to (Fe,Cr)2B, spheroidal non-equilibrium Fe23(CB)6-type borides were also found inside the austenite dendrites. The eutectic liquid rich in boron and Fe, which has low solidus temperature, contributes significantly to backfilling of hot cracks formed during welding. This was confirmed through characterization of eutectic borides in the as-solidified structure which shows Fe-rich (Fe,Cr)2B and Fe23(CB)6 types of borides. Finally, reasons behind severe liquation cracking of 304B4 SS observed during fabrication of neutron shield has been explained based on Scheil’s solidification simulations.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13

Similar content being viewed by others

References

  1. Brown RS (1992) Borated stainless steels (ASTM A887-88) a comparison of grade A neurosorb plus and grade B neurosorb plus. Nuclear-Engineering-International 37(455):41–42

    Google Scholar 

  2. Robitsch J (1971) Interstitial elements and their compounds as well as intermetallic Precipitates in stainless steel. Habilitationsschrifi Montanuniversitat, Leoben

    Google Scholar 

  3. Malissa H, Grasserbauer ME, Hoke ea (1977) Contribution to the characterization of high boron chromium-nickel-molybdenum-copper steels by means of stereometric analysis. Mikrochim Acta (Vienna) 67:73–91

    Article  Google Scholar 

  4. Donati JR, Guttmann D, Zacharie G (1974) Influence of boron content on tendencea hot cracking in the areas affected by welding of stainless steels 18/10. Rev Metal 71:917–930

    Article  CAS  Google Scholar 

  5. Shinodo T, Miyake H, Matsuzaka T (1992) Hot cracking susceptibility of boron added 304 type stainless steel welds. Mater Sci Technol 8(10):913–921

    Article  Google Scholar 

  6. Kumar P, Pai A (2014) An overview of welding aspects and challenges during manufacture of intermediate heat exchangers for 500mwe prototype fast breeder reactor. Procedia Engineering 86:173–183

    Article  CAS  Google Scholar 

  7. Brooks JA, Thompson AW, Williams JC (1984) A fundamental study of the beneficial effects of ferrite in reducing weld cracking. Weld J 63:71s–83s

    Google Scholar 

  8. Srinivasan G, Divya M, Das CR, Albert SK, Bhaduri AK (2015) Weldability studies on borated stainless steel using Varestraint and Gleeble tests. Weld World 59:119–126

    Article  CAS  Google Scholar 

  9. Robino CV, Cieslak MJ (1995) Fusion welding of a modern borated stainless steel. Metall Mater Trans A 26(7):1673–1685

    Article  Google Scholar 

  10. Goldschmidt HJ (1971) Effect of boron additions to austenitic stainless steels - part II: solubility of boron in 18%Cr, 15%Ni austenitic steel. J Iron Steel Inst 209(11):910–911

    CAS  Google Scholar 

  11. Sigolo E, Soyama J, Zepon G, Kiminami CS, Botta WJ, Bolfarini C (2016) Wear resistant coatings of boron-modified stainless steels deposited by plasma transferred arc. Surf Coat Technol 302:255–264

    Article  CAS  Google Scholar 

  12. Shankar V, Gill TPS, Mannan SL, Sundaresan S (2003) Effect of nitrogen addition on microstructure and fusion zone cracking in type 316L stainless steel weld metals. Mater Sci Eng A343:170–181

    Article  CAS  Google Scholar 

  13. Li L, Messler RW (2002) Dissolution kinetics of NbC particles in the heat-affected zone of type 347 austenitic stainless steel. Metall Mater Trans A 33:2031–2042

    Article  Google Scholar 

  14. Kayser FX, Kayser GF (1999) A re-examination of the Kraft and Flinn diffraction data for Cr2B, (Cr,Fe)2B, and the boride phase in Fe + 18.5 wt % Ni + 20 wt % Cr + B alloys. J Mater Sci 34:1271–1275

    Article  CAS  Google Scholar 

  15. Akitoshi Mizuno, Jin Tamura , Shinji Kohara et al: Time-resolved X-ray diffraction study on solidification of Fe-B and Fe-C eutectic alloys. Mater Sci Forum, 2012; 706-709:1703–1706

  16. Quirinale DG, Rustan GE, Kreyssig A, Goldman AI (2015) Synergistic stabilization of metastable Fe23B6 and γ-Fe in undercooled Fe83B17. Appl Phys Lett 106:241906. https://doi.org/10.1063/1.4922802

    Article  CAS  Google Scholar 

  17. Glasson DR, Jones JA (1969) Formation and reactivity of borides, carbides and silicides I. Review and introduction. J Appl Chem 19:125–137

    Article  CAS  Google Scholar 

  18. Ma S, Xing J, Fu H, Gao Y, Zhang J (2012) Microstructure and crystallography of borides and secondary precipitation in 18 wt.% Cr-4wt.% Ni-1wt.%Mo-3.5wt.%B-0.27wt.%C steel. Acta Mater 60:831–843

    Article  CAS  Google Scholar 

  19. Kaneko H, Nishizawa T, Chiba A (1966) Borides in stainless steel. J Japn Inst of Metals 30(2):157–163

    Article  CAS  Google Scholar 

  20. Huang C, Cao G, Kou S (2004) Liquation cracking in partial penetration aluminium welds: assessing tendencies to liquate, crack and backfill. Sci Technol Weld Join 9(2):149–157

    Article  CAS  Google Scholar 

Download references

Acknowledgments

The authors would like to thank Mrs. Sreevidya for scanning electron microscopy and Dr. Paneerselvam, Chemistry group for XRD studies.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to M. Divya.

Additional information

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Recommended for publication by Commission IX - Behaviour of Metals Subjected to Welding

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Divya, M., Albert, S.K. & Paul, V.T. Characterization of eutectic borides formed during solidification of borated stainless steel 304B4. Weld World 63, 1681–1693 (2019). https://doi.org/10.1007/s40194-019-00786-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s40194-019-00786-1

Keywords

Navigation