Ductile iron pipes require a meticulous identification process; they are primarily used for high-pressure fluid transportation, and are also known as daily welding pipes or black pipes. Compared to焊接管(welded pipes), ductile iron pipes are mainly used for transporting water, gas, atmosphere, oil, and heating steam, among other high-pressure fluids. Their characteristics include a smooth inner wall, lightweight, corrosion resistance, good anti-scale performance, and low cost. However, they also have several drawbacks, notably: aging, significant thermal expansion and contraction, unsuitability for long-term exposure to sunlight, poor compressive strength, and poor workability during construction, leading to poor deformation and flexibility. The raw materials for ductile iron pipes are alloyed with magnesium, calcium, and other alkaline earth metals or rare metals.

Ductile iron pipes are forged using continuous casting and water-cooled centrifugal forging methods, with the latter being a modern technique. Compared to simple cast iron pipes, the water-cooled method not only improves corrosion resistance but also boasts high strength, excellent toughness, thin walls, light weight, excellent impact resistance, great bending capabilities, and easy installation. It has also been widely used domestically.