Effects on Microstructure and Corrosion Behavior of a Heat Treated CuZn36Pb2 Brass

Abstract:

The brass CuZn36Pb2 is widely used for fittings, valves and other installation materials. Failures are observed occasionally caused by corrosion. Considering the Cu-Zn phase diagram only α-phase exists in the range of 650 and 300 °C. At higher temperatures α- and β-phase is stable and at lower temperatures α- and β´-phase exist. Since the β-phase is Zn-enriches, it is attacked severely by corrosion. In the recent work brass samples were heat treated at temperatures between 850 and 200 °C to study the microstructural changes and the corresponding electrochemical properties. Potentiostatic corrosion tests were applied in artificial fresh water and sea water at different potential settings. After a heat treated at 850 °C the brass has formed b-phase which can be shown by metallography. At lower temperatures the microstructure is fine grained and no β-phase was observed. To verify the presence of β´-phase a heat treatment at 200 °C was performed but no β´-phase was observed, which was confirmed additionally by X-ray diffraction. Again, after corrosion tests the samples were investigated by metallography and the β-phase was obviously more attacked than the α-phase.

• Periodical: Defect and Diffusion Forum (Volume 405)
• Pages: 333-338
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.405.333
• Online since: November 2020
• Authors: Roland Haubner*, Susanne Strobl, Paul Linhardt
• Keywords: Brass, Corrosion Tests, Fresh Water, Heat Treatment, Sea Water

References

[1] Kupfer-Zink-Legierungen (Messing und Sondermessing), Deutsches Kupferinstitut, 03/(2007).

[2] L. Yohai, M. Vázquez, M.B. Valcarce, Brass corrosion in tap water distribution systems inhibited by phosphate ions, Corrosion Science 53 (2011) 1130-1136.

DOI: 10.1016/j.corsci.2010.12.005

[3] E. Sarver, M. Edwards, Effects of flow, brass location, tube materials and temperature on corrosion of brass plumbing devices, Corrosion Science 53 (2011) 1813-1824.

DOI: 10.1016/j.corsci.2011.01.060

[4] M.B. Valcarce, S.R. de Sánchez, M. Vázquez, Brass dezincification in a tap water bacterial suspension, Electrochimica Acta 51 (2006) 3736-3742.

DOI: 10.1016/j.electacta.2005.10.034

[5] T.B. Massalski, Binary Alloy Phase Diagrams, ASM International, Metals Park OH (1990).

[6] S. Gialanella, L. Lutterotti, Metastable structures in α-β brass, Journal of Alloys and Compounds 317-318 (2001) 479-484.

DOI: 10.1016/s0925-8388(00)01374-8

[7] G.F. Van der Voort, Metallography – Principles and Practice, ASM International, 3rd printing, (2004) 642.

[8] P. Linhardt, S. Kührer, G. Ball and M.V. Biezma, Materials and Corrosion 69 (2018) 358-364.

[9] European Standard EN 1982:2008, Copper and copper alloys - ingots and castings,.

[10] P. Zhou, M.J. Hutchison, J.W. Erning, J.R. Scully and K. Oglea, An in situ kinetic study of brass dezincification and corrosion, Electrochimica Acta 229 (2017) 141-154.

DOI: 10.1016/j.electacta.2017.01.078