As the name implies, ductile iron pipe is a kind of cast iron pipe. Besides ductile iron pipes, other types of cast iron pipes include gray cast iron pipes and cement cast iron pipes. Ductile iron pipe is a kind of water supply pipe formed by centrifugal casting after spheroidization of blast furnace molten iron. Due to spheroidizing treatment, ductile iron pipes have good plasticity, toughness and mechanical properties, which are widely used in municipal pipe networks, water supply pipe networks and large-scale water conservancy projects, and are the dominant pipes in the water supply field.

1. Specification for Ductile Iron Pipe

K9 grade ductile iron pipes, also known as national standard ductile iron pipes, are divided into Dn80-Dn2600 according to their nominal diameters.

2. Characteristics of ductile iron pipes

( 1)? bearing capacity

Water supply network is usually buried underground, which will inevitably be affected by loads from land and vehicles. Ductile iron pipe itself has the properties of iron and steel, which can ensure that the pipe can effectively resist external loads and be laid more economically.

(2)? Hydraulic performance

At the peak of water consumption, ductile iron pipes can withstand higher internal pressure; In addition, the nodular cast iron pipe is lined with cement mortar, and its equivalent roughness k value is 0.030mm；;

(3)? airtightness

Ductile iron pipes adopt flexible joints, which can effectively prevent various forms of infiltration and erosion and greatly reduce the leakage rate of pipeline joints after strict sealing tests.

(4)? Anticorrosive performance

Cement mortar lining is often used for internal corrosion protection of ductile iron pipes, and zinc spraying process and asphalt spraying topcoat are used for external corrosion protection, which can effectively isolate bad water quality and corrosive soil erosion.

3.？ Production technology of nodular cast iron pipe

Blast furnace molten iron-molten iron refining-spheroidizing treatment-core making-centrifugal casting-annealing furnace-ring cutting and rounding-zinc spraying-three grinding-hydrostatic test-cement lining-cement solidification-lining grinding-socket/pipe body painting-pipe body identification painting-finished product warehousing.

4.？ Application of Ductile Iron Pipe

Municipal company pipe network, water plant long-distance transportation, municipal sewage pipeline, urban-rural integration pipe network

5. Comparison between ductile iron pipe and other water supply pipes

Compared with stainless steel pipe, ductile iron pipe joint adopts flexible joint, which has low leakage rate and can achieve the purpose of high efficiency and water saving.

Compared with PE pipe, ductile iron pipe has higher internal pressure safety factor, better internal and external corrosion resistance, longer service life, lower installation difficulty and simpler and faster.