Ductile Iron (also known as Spheroidal Graphite Iron or Nodular Cast Iron) was invented in 1949. Ductile Iron retains the corrosion resistance of Cast Iron but has more than double the tensile strength [Cast Iron- 180 MPa (min), Ductile Iron - 420 MPa (min)]. The essential difference between Ductile and Cast Iron lies in the shape of the graphite in the microstructure of the metal. In Cast Iron, the graphite is present in plate-like flakes, which makes Cast Iron brittle. But in Ductile Iron, the shape of the graphite becomes a spheroidal nodule, which offers better mechanical properties and makes Ductile Iron sturdy, structurally stronger and shock-proof.

Why Ductile Iron Pipes?

Ductile Iron Pipes are preferred due to the following reasons:

High Tensile Strength

Ductile iron offers higher Tensile Strength than Mild Steel and retains the inherent corrosion resistance of Cast Iron due to its spheroidal graphite micro-structure. Pipes made from Ductile Iron provide substantial benefits in terms of pressure bearing ability, impact resistance and capacity to sustain external static/ dynamic loading.

Flexible and Leak Tight Joints

Ductile Iron Pipes have flexible push-on joints which do not leak at high or low pressure, even when deflected. Thus, these pipes are flexible, easy and quick to join.

Corrosion Resistant

Ductile iron pipes with external metallic zinc/epoxy coating with finishing layer of Bituminous Coating and internal cement mortar lining using large centrifugal force provides excellent anti-corrosive properties

Longer Service Life

Ductile iron Pipes have very long reliable service life of 70-90 years.

Detail of Pipes
  • Ductile Iron Socket and Spigot Pipes with push-on joints
  • Ductile Iron Flanged Pipes of customized lengths.
Ductile Iron Socket and Spigot Pipes:
Product Range

Ductile Iron Socket and Spigot Pipe with Push-On Joint conforming to IS 8329 : 2000 with subsequent amendments for Water and Sewerage.

Nominal Diameter(mm) Class Standard Length(m)
100 to 1100 K7, K9 For 100mm to 300mm - 5.5m, 350mm to 600mm – 5.5m or 6m, 700mm to 1100mm – 6m
Coating and Lining:

Internal Lining – standard product

Cement mortar lining with Portland Slag cement (IS: 455:1989) or Sulphate Resisting Cement (IS:12330:1988) conforming to Annex B of IS 8329:2000.

External Coating – standard product

Metallic Zinc Coating as per annex A of IS 8329 with finishing layer of Bituminous Coating as per Annex C of IS 8329.

Other linings and Coatings

High Alumina Cement mortar lining, Epoxy Coating and Polyethylene Sleeves can be provided for specific conditions.

For more information click here (Product catalogue to be attached)

DI Flanged Pipes

DI Flanged Pipes: Flanged joints are the most common type of rigid joint, which are available with single flange or double flanges with optional puddle flange

SPL manufactures DI flanged pipes as per clause 6.2 of IS 8329:2009 with following types of joints:

Welded Flange Joints

Flanges are pre-heated to around 6000C and shrink fit to the pipes after ensuring perpendicularity and holes alignment. The flanges are then welded to the pipes using automatic MIG welding under argon atmosphere and high nickel containing wire .This automatic process ensures uniform weld bead all around the circumference.

Screwed Flange Joint

Threading of pipes and flanges are done in lathes fitted with special attachments. Using jigs and fixtures it is ensured that the bolt hole circle of the flange is concentric with the bore of the pipe and the holes of the flanges at the two ends are correctly aligned. Sealing compound suitable for use with raw water, potable water gas and domestic sewage is being applied. The screwing/tightening of the flanges to the pipes is done using a special purpose machine.

After tightening, all the pipes are subjected to pressure testing.

As per Amendment No.3, Feb 2014 to IS 8329:2000 "Welding on flanges will not be allowed on the screwed flange pipe"

Size range Flanging Methodology Length PN type Class of pipe
100-450 Welding/Screwing method 0.5m to 5.5m Any length PN 10 K9
500-1000 Welding method 0.5m to 5.5m Any length PN 16 K9
Coating /Lining:

The pipes are supplied with inside Cement Mortar Lining and outside Zinc Rich Epoxy Paint followed by Bituminous coating or Blue Epoxy coating.

DI Flange Pipe Application:
  • Fire fighting System
  • Overhead Tanks / Elevated Service reservoirs.
  • Where frequent disengagement of pipe line requires for maintenance purpose
  • Canal, Road Crossing or Bridges
  • Hilly areas
  • Interconnection in STPs or WTPs

The technical data given in this site is for information purpose. It is subject to change without notice, hence legally not bind.

For more information click here (Product catalogue to be attached)


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