The strength, durability, and long service life of Ductile’s predecessor, gray Cast Iron pipe, are widely recognized. The first official record of Cast Iron pipe installation was in 1455 in Siegerland, Germany. In 1664, French King Louis XIV ordered the construction of a Cast Iron pipe main extending 15 miles from a pumping station at Marly-on-Seine to Versailles to supply water to the fountains and town. This pipe served the palace gardens for more than 330 years.
Cast Iron pipe was introduced to the United States as early as 1817, when it was installed in the Philadelphia water system. Today, more than 600 utilities (in the United States and Canada) have had Cast Iron mains in continuous service for more than 100 years. Additionally, at least 21 utilities have had Cast Iron mains in continuous service for more than 150 years.
Stronger and Tougher than Cast Iron for Unmatched Dependability
Ductile Iron not only retains all of Cast Iron’s attractive qualities, such as machinability and corrosion resistance, but also provides additional strength, toughness, and ductility. It is lighter, stronger, more durable and more cost effective than Cast Iron.
Although its chemical properties are similar to those of Cast Iron, Ductile Iron incorporates significant casting refinements, additional metallurgical processes, and superior quality control.
Ductile Iron’s improved qualities are derived from an improved manufacturing process that changes the character of the graphite content of the iron. Ductile Iron’s graphite form is spheroidal, or nodular, instead of the flake form found in Cast Iron. This change in graphite form is accomplished by adding an inoculant, usually magnesium, to molten iron of appropriate composition during manufacture.
Due to its spheroidal graphite form, Ductile Iron has approximately twice the strength of Cast Iron as determined by tensile, beam, ring bending, and bursting tests. Its impact strength and elongation are many times greater than Cast Iron’s.
Why Ductile Iron Pipe Defines Durability: The Stuff Legends Are Made Of
Since its introduction into the marketplace in 1955, Ductile Iron pipe has been recognized as the industry standard for modern water and wastewater systems. More than four decades of field experience have proven its strength, durability, and reliability for transporting raw and potable water, sewage, slurries, and process chemicals.
Ductile’s high degree of dependability is primarily due to its high strength, durability, and impact and corrosion resistance. Ductile Iron has minimum strength requirements of 60,000 psi tensile strength, 42,000 psi yield strength, and 10 percent minimum elongation. Designed and manufactured to the industry’s most stringent standards, Ductile Iron pipe resists damage during shipping and handling, and, once installed, withstands the most demanding operating conditions, including water hammer, frozen ground, deep trenches, areas of high water table and heavy traffic, river crossings, pipe on supports, rocky trenches, and areas of shifting, expansive, and unstable soils. Additionally, numerous laboratory and field tests have proven that Ductile Iron’s corrosion resistance is equal to or greater than that of Cast Iron, which has a service history that is unequaled by any other piping material.
Installation is simple. Unlike some pipe materials, Ductile Iron pipe requires no complex line-and-grade drawings or laying schedules. It can be installed in a wide variety of trench and standard laying conditions and can be easily cut in the field. Direct tapping, even in straight lines, doesn’t affect its integrity. And, once installed, Ductile Iron pipe is virtually maintenance-free.
The pipe is manufactured in 18- or 20-foot nominal laying lengths and 3- to 64-inch diameters in a range of standard pressure classes and nominal wall thicknesses. Ductile Iron is furnished with several different types of joints and a wide variety of standard fittings is available without special order. Although Ductile Iron is usually furnished with cement-mortar lining, optional internal linings are also available for a wide range of special applications.
And Ductile Iron’s generally larger than nominal inside diameters, combined with its high flow coefficient (C = 140), offers substantial savings on pumping and power costs over the life of the pipeline.
Ductile Iron pipe is the kind of pipe that utility engineers dream of. Its reliability, derived from its strength and adaptability, give those engineers the peace of mind that can only come from using a product that they know will be there when duty calls. They know that the good service they demand for their customers follows directly from their decision to install Ductile Iron pipe … the Right Decision