Experiences with Inconel 625 in Biomass and Waste Incineration Plants


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Inconel 625 is utilised in both biomass and waste incineration plants in Denmark. In both cases, the performance is good however the morphology of corrosion attack is different which indicates different corrosion mechanisms. In waste incineration plants there is general attack and shallow pitting, and in some cases dendritic attack especially on the fins of waterwalls. The dendritic attack is in the dendritic core. The presence of pits or dendritic attack is linked to the temperature of the metallic surface and the molten salt composition. In a woodchip biomass plant, chromium depletion was observed on the surface of the weld overlay leaving behind a nickel and molybdenum rich porous structure. The corrosion attack was not related to the dendritic microstructure of the weld. In two straw-fired biomass plants, co-extruded Sanicro 63 (alloy 625 type) as well as Inconel 625 weld overlay revealed the same type of attack, again chromium depletion. This indicates that the corrosion mechanism in woodchip and straw power plants are similar. Another interesting result in straw-fired boilers was that Nibas welds (alloy 625 composition) could provoke excessive corrosion in adjacent 18-8 stainless steels indicating a galvanic reaction. The corrosion mechanisms observed in each case are discussed in relation to temperature and corrosive environment.



Materials Science Forum (Volumes 522-523)

Edited by:

Shigeji Taniguchi, Toshio Maruyama, Masayuki Yoshiba, Nobuo Otsuka and Yuuzou Kawahara




M. Montgomery et al., "Experiences with Inconel 625 in Biomass and Waste Incineration Plants", Materials Science Forum, Vols. 522-523, pp. 523-530, 2006

Online since:

August 2006




[1] M. Montgomery and O.H. Larsen: NACE Corrosion Conference 2005 at Houston, Paper 05309.

[2] M. Montgomery and A. Karlsson: Materials and Corrosion 50, (1999), pp.579-584.

[3] M. Montgomery, A. Karlsson and O.H. Larsen: Materials and Corrosion 53 (2002), p.121.

[4] N. Henriksen, M. Montgomery and O.H. Larsen: Proceedings of VDI Conference (2002).

[5] M. Montgomery, O.H. Larsen and O. Biede: NACE Corrosion Conference 2003 at San Diego, Paper 03356.

[6] M. Montgomery and O.H. Larsen: Corrosion Investigation at Måbjerg, Internal report (2004).

[7] M. Spiegel: Materials and Corrosion 50, (1999), p.379.

[8] T. Herzog, W. Schmidl: Rauchgasseitige Dampferzeugerkorrosion pp.345-353. Edt. M. Born Publ SAXONIA Freiburg (2003).

[9] M. Montgomery, B. Carlsen, O. Biede and O.H. Larsen: NACE Corrosion Conference 2002, Paper 02379.

[10] T. Ishitsuka and K. Nose: Materials and Corrosion Vol. 51 (2000) pp.177-181.

[11] Y. Kawahara: Corrosion Science 44 (2002) pp.223-245.

[12] M. Noguchi et al: Materials and Corrosion 51 (2000) pp.774-785.

[13] Y. Kawahara: Materials at High Temperatures 14 (3) 1997 pp.269-276.

[14] C. Højerslev, N. Tiedje and J. Hald: Proc. of 4th Internat. Conf. on Solidification and Gravity, Hungary, (2004).

[15] R. Bender and M. Schütze: Materials and Corrosion Vol. 54 (2003), p.567.

[16] C. Schwalm and M. Schütze: Materials and Corrosion Vol. 51 (2000), p.73.

[17] D. Berztiss et al: Z. Metallkunde 90 (1999) p.1.

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