DUCTILE IRON FITTINGS



 GUIDELINES FOR FACTORY INSPECTION OF DUCTILE IRON FITTINGS (IS 9523:2000)

1) Marking:

Each fittings shall have as cast, stamped or indelibly painted on it, the following appropriate marks.

a) Indication of the source of manufacture,

b) The nominal diameter,

c) The last two digits of the year of manufacture,

d) PN rating of flanges when applicable, and

Marking may be done on the barrel of castings or on the outside of the sockets.

2) Sampling (as per11606-1986):

      Scale of sampling and criteria for acceptance for dimensional requirements, Mass and straightness of pipes

Lot size

Sample size

Acceptance No.

 Up to 50

8

0

51 to 100

13

1

101 to 150

20

1

151 to 300

32

2

301 and above

50

3

3) Mechanical Tests:

-Tensile Test: The results of test shall show a minimum tensile strength of 420 Mpa (N/mm2)

Nominal Diameter

Type of castings

Tensile strength (Min)

   (MPa)

Elongation at Break percent (Min)

1

2

3

4

All sizes

Fittings

420

5

Brinells Hardness Test: Brinell hardness should not exceed 250 HBS.

If the tests of (i) &(ii) fails for the first time again two samples should be collected for further doing the same tests then also if we get negative results the lot be treated as not complying with standards.

4) Hydrostatic Test

    - For hydrostatic tests, the fittings shall be kept under pressure for 10sec.

   - The fittings shall withstand the Pressure given below

Nominal Diameter

Hydro Test pressure at works, Mpa

Up to and including   300 mm

2.5

Over 300 mm and up to and including 600 mm

1.6

   - They shall withstand the pressure without showing any leakage, sweating or other defect of any  kind. Coating:  After Inspection and Hydro test each fitting shall be coated

Dimensions of fittings:

Nominal Diameter(DN)

External Diameter DE

Wall Thickness, e (mm)

 

Nominal

Tolerance

K12

K14

Tolerance

80

98

+1, -2.7

7

8.1

-2.38

100

118

+1, -2.8

7.2

8.4

-2.4

125

144

+1, -2.8

7.5

8.7

-2.42

150

170

+1, -2.9

7.8

9.1

-2.45

200

222

+1, -3.0

8.4

9.5

-2.50

250

274

+1, -3.1

9

10.5

-2.55

300

326

+1, -3.3

9.6

11.2

-2.60

350

378

+1, -3.4

10.2

11.9

-2.65

400

429

+1, -3.5

10.8

12.6

-2.70

450

480

+1, -3.6

11.4

13.3

-2.75

500

532

+1, -3.8

12

14.0

-2.80

600

635

+1, -4.0

13.2

15.4

-2.90

700

738

+1, -4.3

14.4

16.8

-3.0

750

790

+1, -4.4

15.0

17.5

-3.05

800

842

+1, -4.5

15.6

18.2

-3.10

900

945

+1, -4.8

16.8

19.6

-3.20

1000

1048

+1, -5.0

18.0

21.0

-3.30

1100

1152

+1, -5.4

19.2

21.4

-3.40

1200

1255

+1, -5.8

20.4

23.8

-3.50

1400

1462

+1, -6.6

22.8

26.6

-3.70

1500

1565

+1, -7.0

24.00

28.0

-3.80

1600

1668

+1, -7.4

25.2

29.0

-3.90

1800

1875

+1, -8.2

27.6

32.2

-4.10

2000

2082

+1, -9.0

30.0

35.0

-4.30

Where e=K(0.5+0.001DN)

If K=14, e=7+0.014DN and if K=12, e=6+0.012DN

Tolerances on the wall thickness and flange thickness of fittings are limited as follows:

Wall thickness

Tolerance, mm

 

Flange Thickness, mm

Tolerance

7, Greater than 7

-2.3,

-(2.3+0.001DN)

Integrally Cast flanges

Welded and screwed on flanges

±(3+0.05b)

±(2+0.05b)

Where,

b = the standard thickness of the flange in mm.

Tolerances on lengths of fittings, normally manufactured, shall be as follows:

Type of Fitting

Nominal Dia

Tolerance mm

Flanged Sockets Flanged spigots

Collars, tapers

80 to 1200

1400 to 2000

± 25

± 35

 

Tees

80 to 1200

1400 to 2000

+50,  -25

+75,  -35

Bends 90 deg(1/4)

Bends 45 deg(1/8)

80 to 2000

80 to 2000

±(15+0.03 DN)

±(10+0.025 DN)

 

Bends 22 deg 30’ and 11 deg 15’

(1/16 and 1/32)

80 to 1200

1400 to 2000

±(10+0.02 DN)

±(10+0.025 DN)

 

Tolerances on height of raised face (c) in mm

Height of raised face (c)

Tolerance

3

+1.5

-2.0

4

+2.0

-3.0

5

+2.5

-4.0

Tolerances on Flange drilling in mm

 

Bolt Hole Dia

Dimension

Dia 19 to 28

Dia 31 to 56

Above dia 62

Bolt hole dia, d

+2

-0

+3, -0

+4, -0

PCD, C

±2.0

 

±2.8

 

±4.8

C/C of adjacent bolt holes

±2.0

 

±2.8

 

±4.8

Tolerance on the External diameter “D” in mm

Nominal Diameter

80,100,125

150,200,250,300

350,400,450,500,600

Tolerance on D

Tolerance on E

±4.5

±4.0

+5.5, -2.5

±4.5

+6.5, -3.5

±5.0

Nominal Diameter

700,750,800,

900,1000

1100,

1200

1400

1600, 1800, 2000

Tolerance on D

Tolerance on E

+7.5, -4

±5.5

+8.5, -4

±5.5

+10, -5

±6.0

±12, -6

±6.0

ZINC COATING

 MATERIALS

The coating materials are metallic zinc with content of at least 99 percent by mass or Zinc rich paint which contains 85 percent Zinc in Dry film.

  Zinc Coating Mass :

The mean mass of zinc coating measured shall be not less than 130 g/m2 with a local minimum of 110 g/m2. In case of zinc rich paint the mean mass is 150 g/m2 and the local minimum value is 130 g/m2.

Finishing layer

The mean dry film thickness of the finishing layer shall be less than 70 µm with a less minimum thickness of 50 µm

CEMENT MORTAR LINING

Thickness of Lining

 

DN

Thickness

Maximum crack Width and Radial Displacement

Nominal Value

Tolerance

80 to 300

3.0

-1.5

0.8

350 to 600

5.0

-2.0

1.0

700 to 1200

6.0

-2.5

1.2

1400 to 2000

9.0

-3.0

1.5

BITUMINOUS COATING:

The mean thickness of the coating shall be-not less than 70 µm and the local minimum thickness shall be not less than 50 µm.

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