Ductile Iron Spun Pipe & Ductile Iron Flanged Pipe Cast

Ductile Iron Pipes as per IS 8329; ISO 2531: ISO 7186 ; BS EN 545 ; BS EN 598

Ductile Iron Pipes (Cast Iron Pipes)
Carbon steel pipes manufacturer & supplierDuctile 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 differences 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.

Ductile Iron pipe is considered as the most preferred pipe material for water supply and pressure sewerage application all over the world. It offers higher Tensile Strength than Mild Steel and retains the inherent corrosion resistance of cast iron. Pipes made from Ductile Cast Iron, provides substantial benefits in terms of pressure bearing ability, impact resistance and capacity to sustain external static/ dynamic loading.

 

Range of Pipes

Ductile Iron Spun Pipes are produced in both as per Thickness Class (like, K9, K7 etc) and Pressure Class (Like C25, C30, C40 etc). The Standard Products are listed below.

Size – DN 80 mm to DN 1000 mm
Pressure Class – C20, C25, C30, C40, C50, C64, C100.

Thickness Class – K9 and K7
Standard Length – 5m / 6.0 meters

Conforming Specifications:IS 8329; ISO 2531: ISO 7186; BS EN 545; BS EN 598

Types-

A. Ductile Iron Socket and Spigot Pipe with Push-On Joint from DN 80 to DN 1000 with Rubber Gasket conforming to IS 8329/ ISO 2531/ EN 545/ EN598 for Drinking Water and sewerage. Ductile Iron pipes are available in the following Joints
Push-on
Push On (Restrained)
B. Ductile Iron Flanged Pipe from DN 80 to DN 1000 conforming to IS 8329/ ISO 2531 / EN 545. Flanged Pipes are available
As cast (Small Barrel lengths)
Welded on
Screwed on

Properties of Ductile Iron Pipe

Properties Ductile Iron Pipe
Tensile strength Min. 420 MPa
Elongation (min) at break 10%
Modulus of Elasticity 1.7×1010 Kg/M2
Hardness Max. 230 BHN

Inside Lining
Ductile Iron Pipes installed in water systems today are normally provided with cement mortar lining. Use of cement lining of the pipe avoids tuberculation by creating a high pH at the pipe wall, and ultimately by providing a physical barrier to the flow water to contact with the pipe wall. Further, linings are also smooth, which results in high coefficients with Haizen Willams C as 140 (Colebrook coefficient k = 0.1). In case of sewerage application, suitable lining will provide corrosive resistance to septic transformation (cycle of sulphates, sulphuric acid) to avoid severe carrion to pipe wall. The advantages of internal cement mortar lining are:

  • Internal protection of pipe wall against fluid aggressiveness
  • Improvement and performance of pipe flow characteristics
  • For potable water pipelines, assurance of keeping water quality within
    specified limits.
  • Withstand against corrosion due to septic transformations.
Type of Lining Material Service Condition Reference standards
Ordinary Portland Cement Drinking water ISO 4179BS EN 197-1
Blast Furnace Slag Cement Drinking water ISO 4179BS EN 197-1
Portland Slag Cement Drinking water ISO 4179BS EN 197-1
Sulphate resistance Cement Raw water/Drinking Water/ Sea water/ Non-septic Sewers ISO 4179BS 4027
High Alumina Cement Septic Sewers / Drinking Water/Acids/ Alkali waters/ Pickling Brine/ Sea water ISO 4179BS EN 14647
Cement Mortar Lining with Bituminous/epoxy Seal Coat Drinking water/ Sewers ISO 4179BS EN 14901

Outside Coating
Intrinsic corrosion resistance of Ductile Iron in various corrosive soils is as least as good as and even somewhat better than that of Cast Iron, as there is not much variation chemically between the two materials. When subjected to corrosion, the nodular graphite of ductile iron pipes forms corrosion by products that adhere firmly to the unattached metal, which provides a barrier against further corrosion. In addition, uniform spreading of spheroidal graphite of ductile iron results in less susceptible to deep localized pitting than that of grey iron pipe, which is important in evaluating its relative resistance to failure by perforation. Due to rubber gasket jointing, ductile pipes are electrically discontinuous. As a result, long line corrosion current, which is dependent on exposure of a single electrical unit to varying soil conditions, cannot develop. Additionally, any accumulation of stray current is limited to short electrical units and usually is of little significance in developing corrosion.

Additional external protection to ductile iron pipe provides long service performance, especially for smaller diameter pipes where wall thickness is comparatively less. Following external protection is normally being provided:-

S. No. Type of Coating Reference Standards
1 Zinc coating with finishing layer of Bitumen/ Epoxy ISO 8179-1
2 Zinc coating with finishing layer with additional protection by polyethylene sleeving ISO 8180
3 Alloy of Zinc and Aluminum with or without other metals having a minimum mass of 400 gm/m with finishing layer. ISO: 14713

Jointing Systems

  • Socket & Spigot Flexible Push-on Joints
  • Restrained Joint Push-on Type
  • Mechanical Flexible Joints (only fittings)
  • Flanged Joint

Flanges
Flanges are flat rings around the end of pipes which mate with an equivalent flange from another pipe, the two being held together by bolts usually passed through holes drilled through the flanges. A deformable gasket, usually elastomeric, placed between raised faces on the mating flanges provides the seal. Flanges are designed to a large number of specifications that differ because of dimensional variations in pipes sizes and pressure requirements, and because of independent standards development. In the U.S. flanges are either threaded or welded onto the pipe. In the European market flanges are usually welded on to the pipe. In the U.S. flanges are available in a standard 125lb. bolt pattern as well as a 250 lb (and heavier) bolt pattern (steel bolt pattern). Both are usually rated at 250(1,700kPa). A flanged joint is rigid and can bear bothtensionandcompressionas well as a limited degree ofshearandbending. It also can be dismantled after assembly. Due to the rigid nature of the joint and the risk of excessive bending moment being imposed, it is advised that flanged pipework is not buried.

Spigot and socket
Spigot and sockets involve a normal pipe end, the spigot, being inserted into the socket or bell of another pipe or fitting with a seal being made between the two within the socket. Normal spigot and socket joints do not allow direct metal to metal contact with all forces being transmitted through the elastomeric seal. They can consequently flex and allow some degree of rotation, allowing pipes to shift and relieve stresses imposed by soil movement. The corollary is that unrestrained spigot and socket joints transmit essentially no compression or tension along the axis of the pipe and little shear. Any bends, tees or valves therefore require either a restrained joint or, more commonly, thrust blocks, which transmit the forces as compression into the surrounding soil.A large number of different socket and seals exist. The most modern is the ‘push-joint’ or ‘slip-joint’, whereby the socket and rubber seal is designed to allow the pipe spigot to be, after lubrication, simply pushed into the socket. Push joints remain proprietary designs. Also available are locking gasket systems. These locking gasket systems allow the pipe to be pushed together but do not allow the joint to come apart without using a special tool or torch on the gasket.The earliest spigot and socket cast iron pipes were joined by filling the socket with a mixture of water, sand, iron filings and sal-ammoniac (ammonium chloride.)Agaskinring was pushed into the socket round the spigot to contain the mixture which was pounded into the socket with a caulking tool and then pointed off. This took several weeks to set and produced a completely rigid joint. Such pipe systems are often to be seen in nineteenth century churches in the heating system.

Mechanical Flexible Joints

In mechanical joint, sealing is achieved by applying pressure on the gasket by a separate gland. When bolted with the pipe, the gland exerts pressure on the sealing rubber gasket and makes the joint leak proof.

Restrained Joint Push-on Type for Buried Pipes
Restrained Joints are special jointing system, which can take care of axial movement in case of thrust. Hydraulic thrust forces occur in pressurized mains, when there is any change in direction (bends, tees) or any change of diameter (tapers, valves) or any pipeline end (blank flanges or caps). These special joints are necessary on fittings and a few pipes adjacent to the fittings. Restrained Joints eliminate use of concrete anchor blocks, which are costly and delay the progress of laying operation.

Application

  • Raw and clear water transmission (pumping and gravity main)
  • Distribution network of potable water
  • Water supply for industrial /process plant application
  • Ash-Slurry Handling & Disposal system
  • Fire-fighting systems-on-shore and off-shore
  • Desalination Plants
  • Sewerage and waste water force main
  • Gravity sewerage collection and disposal system
  • Storm water drainage piping
  • Effluent disposal system for domestic and industrial application
  • Recycling system
  • Piping work inside water and sewage treatment plants
  • Vertical connection to utilities and reservoirs
  • Piling for ground stabilisation
  • Protective piping under major carriage-ways

Pipe Dimension
Basic Dimension of pipes Class K7 & K9

PRESSURE CLASS

THICKNESS CLASS

Nominal
Dia.
DN
mm

External
Dia.
DE
mm

Tol. on
DE
mm

Preferred
‘C’ class

Preferred
class Nom

Thickness

Nominal
Thickness
K9
mm

ECL
Works Test

Pressure
K9
(Kg/cm)

80

98

+1/-2.7

C40

4.4

6.0

60

100

118

+1/-2.8

C40

4.4

6.0

60

150

170

+1/-2.9

C40

4.5

6.0

60

200

222

+1/-3

C40

4.7

6.3

60

250

274

+1/-3.1

C40

5.5

6.8

60

300

326

+1/-3.3

C40

6.2

7.2

60

350

378

+1/-3.4

C30

6.3

7.7

50

400

429

+1/-3.5

C30

6.5

8.1

50

450

480

+1/-3.6

C30

6.9

8.6

50

500

532

+1/-3.8

C30

7.5

9.0

50

600

635

+1/-4

C30

8.7

9.9

50

700

738

+1/4.3

C25

8.8

10.8

42

800

842

+1/4.5

C25

9.6

11.7

42

900

945

+1/-4.8

C25

10.6

12.6

42

1000

1048

+1/-5

C25

11.6

13.5

42

Note: Preferred ‘C’ class as per ISO2531/2009

Ductile Iron Spun Pipe & Ductile Iron Flanged Pipe Cast dimension

Dimensions of Flange

DN

PN-10

PN-16

D

E

C

b

n

Dia (d)

Metric

D

E

C

b

n

Dia (d)

Metric

Nom.
Dia.

Out
side
Dia

Dia. of
raised
Face

Pitch
Circle
Dia.

Flange
Width

No.
of
Bolts

Bolt
Hole
Dia.

Bolt
Size

Out
side
Dia

Dia. of
raised
Face

Pitch
Circle
Dia.

Flange
Width

No.
of
Bolts

Bolt
Hole
Dia.

Bolt
Size

80

200

132

160

16.0

8

19

M16

200

132

160

16.0

8

19

M16

100

220

156

180

16.0

8

19

M16

220

156

180

16.0

8

19

M16

125

250

184

210

16.0

8

19

M16

250

184

210

16.0

8

19

M16

150

285

211

240

16.0

8

23

M20

285

211

240

16.0

8

23

M20

200

340

266

295

17.0

12

23

M20

340

266

295

17.0

12

23

M20

250

395

319

350

19.0

12

23

M20

400

319

355

19.0

12

28

M24

300

445

370

400

20.5

12

23

M20

455

370

410

20.5

12

28

M24

350

505

429

460

20.5

16

23

M20

520

429

470

22.5

16

28

M24

400

565

480

515

20.5

16

28

M24

580

480

525

24.0

16

31

M27

450

615

530

565

21.0

20

28

M24

640

548

585

26.0

20

31

M27

500

670

582

620

22.5

20

28

M24

715

609

650

27.5

20

34

M30

600

780

682

725

25.0

20

31

M27

840

720

770

31.0

20

37

M33

700

895

794

840

27.5

24

31

M27

910

794

840

34.5

24

37

M33

750

960

857

900

29.0

24

31

M27

970

857

900

36.0

24

37

M33

800

1015

901

950

30.0

24

34

M30

1025

901

950

38.0

24

40

M36

900

1115

1001

1050

32.5

28

34

M30

1125

1001

1050

41.0

28

40

M36

1000

1230

1112

1160

35.0

28

37

M33

1255

1112

1170

45.0

28

43

M39