Pipe Materials: Cast Iron and Ductile Iron

Due to their longevity and performance, much of the piping still in use for water service in North America is ductile iron (DI) and cast iron (CI) pipe. Designed and manufactured to the industry’s most stringent standards, DI pipe resists damage during shipping and handling. Once installed, it withstands the most demanding operating conditions, including water hammer; freeze-thaw cycles; deep trench loadings; areas of high water table and heavy traffic; river crossings; pipe on supports; rocky trenches; and areas of shifting, expansive, and unstable soils. Gray CI pipe was introduced into the U.S. in 1816, perhaps even as early as 1804. In gray CI, most of the carbon is present in the form of interlocking graphite flakes. In DI, an additional step in the treatment of the molten metal during manufacture causes the graphite to take the form of spheroids.