Ductile Iron Pipe

Ductile Iron Pipe

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 nudule, which increase tensile strength and makes Ductile Iron sturdy and shock-proof.

Ductile Iron Pipe is considered as the most preffered pipe material for water supply and pressure sewerage application all over the world. It Offer higher Tensile Strength and diametral stiffness than Mild Steel and retains the inherent corrosion resistance of cast iron.

Pipes made from Ductile Cast Iron, provides substential benefits in terms of pressure bearing ability, impact resistance and capacity to sustain external static/dynamic loading.


Properties Of Ductile Iron Pipe


Properties Ductile Iron Pipe
Tensile Strength Min.420 MPa
Elongation (min) at Break 10%
Elastic Coefficient 1.7x104 Kg/mm²
Modulus Of Elasticity 1.7x1010 Kg/M²
Hardness Max. 230 BHN
Density 7050 Kg/M3
Bending / Beam Strength Over 50 Kg/M3
Crush load and impact load Can take up huge impact load (Charpy over 0.713).
Bursting Strength (min) Factor of Safety against bursting is 8 to 10.

Hydraulic Working Pressure

For K9 & K7 Pipe


Size (DN) Min. Hydrostatic Works Test Pressure (bar) PFA (AOP) MAX (bar) PMA (MOP) MAX (bar) PEA (STP) MAX (bar)
Class K7 Class K9 Class K7 Class K9 Class K7 Class K9 Class K7 Class K9
100 32 50 8 64 12.5 77 17.5 96
150 32 50 8 64 12.5 77 17.5 96
200 32 50 8 62 12.5 74 17.5 79
250 32 50 8 54 12.5 65 17.5 70
300 32 50 8 49 12.5 59 17.5 64
350 25 40 8 45 12.5 54 17.5 59
400 25 40 8 42 12.5 51 17.5 56
450 25 40 8 40 12.5 48 17.5 53
500 25 40 8 38 12.5 46 17.5 51
600 25 40 8 36 12.5 43 17.5 48
700 18 32 8 34 12.5 41 17.5 46
800 18 32 10 32 15 38 20 43
900 18 32 10 31 15 37 20 42
1000 18 32 10 30 15 36 20 41
1100 12 25 29 29 35 35 40 40
1200 12 25 28 28 34 34 39 39

For Class Pipes

PFA MAX [Allowable Operating Pressure] in bar


Size (DN) C20 C25 C30 C40 C50 C64 C100
100 - - - 40 50 64 100
150 - - - 40 50 64 100
200 - - - 40 50 64 100
250 - - - 40 50 64 100
300 - - - 40 50 64 100
350 - - 30 40 50 64 100
400 - - 30 40 50 64 100
450 - - 30 40 50 64 100
500 - - 30 40 50 64 100
600 - - 30 40 50 64 100
700 - 25 30 40 50 64 -
800 - 25 30 40 50 64 -
900 - 25 30 40 50 - -
1000 - 25 30 40 50 - -
1100 20 25 30 40 50 - -
1200 20 25 30 40 50 - -

Technical Specification


Standard Product Ductile Iron Pipe Suitable for Push-on-Joint
Confirming Specification ISO 2531; BS EN 545; BS EN 598 & IS 8329
Class of Pipe K7, K9, C20, C25, C30, C40, C50, C64 & C100
Size Range DN 100 To DN 1200
Standard Length (in Meters) 5.5 or 6.0
Internal Linings Cement Mortar Lining
Ouside Coatings Zinc Coating (13gm/m² or 200gm/m²
Alloy of Zinc And Aluminiumhaving a minimum mass of 400gm/m²
Finishing Layer of Bitumen/Blue Epoxy/Red Epoxy
Outside Onsite Protection Polyethlene Sleeving
Confirming of Joint Area Bitumen/Epoxy

Applicable Standards : BSEN 545:2010, ISO 2531:2009, BSEN 598:2007

Nominal Diameter, External Diameter and Wall Thickness


Nominal Diameter (DN) in mm External Diameter (DE) in mm Tolerance on External Diameter Minimum Barrel Wall Thickness (e)
K7 K9 C 20 C 25 C 30 C 40 C 50 C 64 C 100
100 118 +1/-2.8 3.7 4.7 - - - 3.0 3.5 4.0 4.7
150 170 +1/-2.9 3.7 4.7 - - - 3.0 3.5 4.0 4.7
200 222 +1/-3.0 3.7 4.8 - - - 3.1 3.9 5.0 7.7
250 274 +1/-3.1 4.0 5.3 - - - 3.9 4.8 6.1 9.5
300 326 +1/-3.3 4.3 5.6 - - - 4.6 5.7 7.3 11.2
350 378 +1/-3.4 4.7 6.1 - - 4.7 5.3 6.6 8.5 13.0
400 429 +1/-3.5 4.6 6.4 - - 4.8 6.0 7.5 9.6 14.8
450 480 +1/-3.6 4.9 6.8 - - 5.1 6.8 8.4 10.7 16.6
500 532 +1/-3.8 5.2 7.2 - - 5.6 7.5 9.3 11.9 18.3
600 635 +1/-4.0 5.8 8.0 - - 6.7 8.9 11.1 14.2 21.9
700 738 +1/-4.3 7.0 8.8 - 6.8 7.8 10.4 13.0 16.5 -
800 842 +1/-4.5 8.3 9.6 - 7.5 8.9 11.9 14.8 18.8 -
900 945 +1/-4.8 9.0 10.4 - 8.4 10.0 13.3 16.6 - -
1000 1048 +1/-5.0 9.7 11.2 - 9.3 11.1 14.8 18.4 - -
1100 1152 +1/-6.0 12.0 12.0 8.2 10.2 12.2 16.2 20.2 - -
1200 1255 +1/-6.2 12.8 12.8 8.9 11.1 13.3 17.7 22.0 - -

Various types of lining applied for ductile iron pipes and its application are :


Types of cement Usage Conforming to
Portland Cement/Blast Furnace Cement Drinking water having pH 6.0 to 9.0 ISO:4179
BSEN:545
Sulphate Resisting Cement Raw water/Sea water/Non septic sewers water ISO:4179
BSEN:545
High Alumina Cement Surface water/Domestic waste water/Certain types of industrial effluents BSEN:598

Thickness of cement mortar lining


Reference Specification Size range (DN) Cement lining thickness in mm Maximum crack width & radial Displacement (mm)
Nominal Minimum at one point
BSEN 545 80-300
350-600
700-1200		 4.0
5.0
6.0		 2.5
3.0
3.5		 0.40
0.50
0.60
ISO 2531
ISO 4179		 80-300
350-600
700-1200		 3.0
5.0
6.0		 2.0
3.0
3.5		 0.80
0.80
1.00

Advantages Of Ductile Iron Pipe

  • Welding is possible.
  • Can endure high working pressure.
  • Lightweight and not brittle - easier to handle.
  • Strongest pipe - high tensile and beam strength.
  • and gives a higher Hazen William’s C Value of 140.
  • Withstands severe crushing load and high impact load.
  • Speedy laying/installation due to push-on type jointing.
  • High ring stiffness - takes care of high soil and traffic load.
  • Due to lesser friction -loss offers impressive energy savings.
  • Centrifugally applied Cement Mortar Lining offers a smooth surface.
  • Every DI Pipe is hydro tested at rated pressure at works. Complete safety against surge.
  • Inherently corrosion resistant - also give extra protection by applying inside cement mortar lining and outside coating of zinc with the finishing layer of bitumen/epoxy.