Both ductile iron and low-carbon steel pipe sections are used in the water industry for a variety of applications.
When included in a steel alloy, carbon makes the steel very hard. The percentage of carbon used in mild steel varies depending on the application. The higher the percentage of carbon, the harder and more inflexible the alloy will be. Because mild steel is a low carbon steel, it retains more flexibility than high carbon steel while still being quite sturdy.
Ordinarily, iron is very prone to rust and corrosion. Because of its unique composition, ductile iron is both more flexible and corrosion resistant than other types of iron pipe. In ductile iron, the graphite forms spherical nodules instead of the flakes found in grey iron. This spherical shape lends structural stability to the iron, hindering the formation of cracks and improving ductility (flexibility). Originally, ductile iron was created for gas industry applications, but it is also widely used in the water industry.
Underground ductile iron pipe can last over 100 years if correctly designed and installed. A unique property of ductile iron pipe is that its physical attributes do not change over time. Provided the pipe is not put under more pressure than it is originally designed to handle, corrosion is the only threat to the pipe’s useful life.
