- Title
- Relationship between microstructure and elemental segregation to the long-term corrosion performance of cast iron water pipes
- Creator
- Nicholas, D.; Chaves, I.; Melchers, R.; Petersen, R.; Davies, S.
- Relation
- Corrosion and Prevention 2016. Proceedings of Corrosion and Prevention 2016 (Auckland, New Zealand 13-16 November, 2016)
- Publisher
- Australasian Corrosion Association
- Resource Type
- conference paper
- Date
- 2016
- Description
- Work at the University of Newcastle and by others in developing methodologies for the Condition Assessment of cast iron water mains suggests a degree of correlation between the long- term corrosion rates of various cohorts of cast iron pipes and their method of manufacture. Recent, preliminary data indicates that the older, statically cast pipes perform better than the spun Delavaud pipes introduced into Australasia in 1929 and these, in turn, have better performance than the 'Super Delavaud' pipes manufactured between 1941 and the mid 1970's when cast iron was superseded by Ductile iron material. These observations differ somewhat from the classical conclusions by Romanoff for USmade pipes. Samples from various cast and spun cast iron pipes exhumed in the Sydney and Newcastle region of NSW and originally installed in the period 1909 to 1974 were subjected to metallographic and chemical analysis, as well as a micro hardness survey, in order to determine differences that may account for this behavior. Elemental segregation mapping of minor elements of each pipe sample was also obtained by SEM/EDS. The preliminary results show that elemental segregation of phosphorus, silicon and other elements did not show any pattern that might account for the better corrosion resistance of the older statically cast pipes and that microstructural differences caused by widely different regimes of cooling rate and heat treatment offer the best basis for the corrosion performance variations. However, at this time the precise relationships between complex microstructures and corrosion resistance remain to be established.
- Subject
- cast iron; corrosion; SEM; microstructure
- Identifier
- http://hdl.handle.net/1959.13/1341125
- Identifier
- uon:28671
- Language
- eng
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