Microstructure Evaluation of Heterogeneous Electron Beam Weld between Stabilised Austenitic and ODS Ferritic Steel

Abstract:

The weldability of advanced heat resistant ODS metallic materials in combination with conventional materials is a prior requirement for their wider use in energy production. The microstructure of ODS steels is composed of alpha iron based matrix with dispersed oxide particles. Due to heating during conventional welding, the microstructure and properties of the resulting weld joints are affected and the joints often become the weakest point of the structure. The electron beam welding with its reduced heat affected zone size may be an answer in this. The presented article is focused on thorough metallographic evaluation of the structure of heterogeneous electron beam welds which combine stabilized austenitic stainless steel with the MA956 ferritic ODS steel. EB welded joints were evaluated by light and analytical electron microscopy including EDS and phase EBSD analyses in the as-welded state and after post-weld heat treatment. Mechanical properties of the weld were evaluated from the results of micro hardness profiles. Achieving an appropriate structure of such welds and correct welding parameters are crucial aspects for future successful application of similar joints in energy industry

• Periodical: Materials Science Forum (Volume 891)
• Pages: 185-189
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.891.185
• Online since: March 2017
• Authors: Vít Jan*, Jan Čupera, Pavel Sohaj, Petr Havlik
• Keywords: EBSD, Electron Beam Welding, Heterogeneous Joints, ODS Steel, Oxide Particles

References

[1] A. Czyrska-Filemonovicz, B. Dubiel, Mechanically alloyed, ferritic oxide dispersion strengthened alloys: structures and properties, Journal of Materials Processing Technology 64 (1997) 53-64.

DOI: 10.1016/s0924-0136(96)02553-8

[2] S. Saroja, et al., Development and characterization of advanced 9Cr ferritic/martensitic steels for fission and fusion reactors, Journal of Nuclear Materials 409 (2011) 131-139.

DOI: 10.1016/j.jnucmat.2010.09.022

[3] CH. Zhang, et al., Characterization of the oxide particles in Al-added high-Cr ODS ferritic steels, Journal of Nuclear Materials 417 (2011) 221-224.

DOI: 10.1016/j.jnucmat.2010.12.063

[4] T.S. Chou, Recrystallization behaviour and grain structure in mechanically alloyed oxide dispersion strengthened MA 956 steel, Materials Science and Engineering A 223 (1997) 78-90.

DOI: 10.1016/s0921-5093(96)10473-1

[5] R. Lindau, et al., Mechanical and microstructural characterization of electron beam welded reduced activation oxide dispersion strengthened – Eurofer steel, Journal of Nuclear Materials 416 (2011) 22-29.

DOI: 10.1016/j.jnucmat.2011.01.025

[6] R. Baldev, et al., Building on knowledge base of sodium cooled fast spectrum reactors to develop materials technology for fusion reactors, Journal of Nuclear Materials 386-388 (2009) 935-943.

DOI: 10.1016/j.jnucmat.2008.12.320

[7] G. Filacchionni, et al., Structural and mechanical properties of welded joints of reduced activation martensitic steels, Journal of Nuclear Materials 307-311 (2002) 1563-1567.

DOI: 10.1016/s0022-3115(02)01073-5

[8] Z. Sun, et al., The application of electron beam welding for the joining of dissimilar metals: an overview, Journal of Materials Processing Technology 59 (1996) 257-267.

DOI: 10.1016/0924-0136(95)02150-7

[9] L. Commin, et al., Characterization of ODS (Oxide Dispersion Strengthened) Eurofer dissimilar electron beam welds, Journal of Nuclear Materials. In Press (2012).

DOI: 10.1016/j.jnucmat.2012.11.019

[10] M. Rieth, et al., Specific welds for test blanket modules, Journal of Nuclear Materials 386-388 (2009) 471-474.

DOI: 10.1016/j.jnucmat.2008.12.142

[11] V. Jan, B. Zlámal, Study of heterogeneous welds of heat resistant steels with artificially increased nitrogen content by combination of experimental and computational techniques, Archives of Metallurgy and Materials 53 (2008) 1165-1171.

[12] P. Havlík, P. Šohaj, Electron beam welds of austenitic stainless steels and ODS steels, In: METAL 2013 Conference proceedings 2013. s. ISBN: 978-80-87294-39- 0.

[13] A. Kroupa, et al., Phase diagram in the iron-rich corner of the Fe-Cr-Mo-V-C system below 1000 K, J. Phase Equilib. 22 (2001) 312-323.

DOI: 10.1361/105497101770338824