ductile iron · DN80–DN1200 · K12 · socket T / flange PN10–PN25 · EN 545
Ductile iron fittings
Bends, tees, reducers, collars and flanged pieces in class K12 for T-type sockets and PN10–PN25 flanges
ductile iron · DN80–DN1200 · K9 / C40 · 6 m · ISO 2531 · EN 545
Ductile iron socket pipe
Centrifugally cast socket pipe K9 and C40 with cement mortar lining, DN80–DN1200, 6 m long
ISO 2531:2009EN 545:2010GOST ISO 2531-2012GB/T 13295-2019EN 598:2007+A1:2009ISO 4179:2005K9K10C40C30C25QT450-10
Parameters
| Parameters | |
|---|---|
| Nominal diameter | DN80–DN1200 |
| Class | K9, K10 — by wall thickness; C25, C30, C40 — by pressure |
| Length | 6 m; 5.5 m by agreement with the mill |
| Joint | T-type socket (Tyton), EPDM gasket |
| Internal lining | cement mortar per ISO 4179: 3 mm DN80–DN300, 5 mm DN350–DN600, 6 mm DN700–DN1200 |
| External coating | zinc at least 200 g/m² and bitumen varnish at least 70 µm; zinc-aluminium 400 g/m² on request |
| Mechanical properties | Rm ≥ 420 MPa, A ≥ 10 %, hardness ≤ 230 HB |
Sizes and weight
| DN | Outside diameter DE, mm | Wall e, mm | Barrel weight, kg/m |
|---|---|---|---|
| 80 | 98 | 6.0 | 12.2 |
| 100 | 118 | 6.0 | 14.9 |
| 150 | 170 | 6.0 | 21.8 |
| 200 | 222 | 6.3 | 30.1 |
| 250 | 274 | 6.8 | 40.2 |
| 300 | 326 | 7.2 | 50.8 |
| 350 | 378 | 7.7 | 63.1 |
| 400 | 429 | 8.1 | 75.5 |
| 450 | 480 | 8.6 | 89.8 |
| 500 | 532 | 9.0 | 104.3 |
| 600 | 635 | 9.9 | 137.1 |
| 700 | 738 | 10.8 | 174.0 |
| 800 | 842 | 11.7 | 215.2 |
| 900 | 945 | 12.6 | 260.2 |
| 1000 | 1048 | 13.5 | 309.3 |
| 1200 | 1255 | 15.3 | 420.1 |
Description
Pressure pipe in ductile (spheroidal graphite) iron for water supply and sewerage: a socket for a rubber gasket at one end, a spigot at the other. The pipe is cast centrifugally — after magnesium treatment the liquid iron is poured into a rotating water-cooled mould, and centrifugal force forms a dense wall of constant thickness. After casting the pipe is annealed to a ferritic structure: tensile strength not less than 420 MPa, elongation not less than 10 % for DN up to 1000 and not less than 7 % for DN above 1000, hardness not more than 230 HB.
Wall thickness is set by class. K9 follows the formula e = 9·(0.5 + 0.001·DN), not less than 6 mm: 6.0 mm for DN100, 7.2 mm for DN300, 9.9 mm for DN600. Classes C25, C30 and C40 to EN 545:2010 and ISO 2531:2009 are defined by the allowable operating pressure in bar, and at the same DN the wall comes out thinner than K9. Inside — a centrifugally applied cement mortar lining to ISO 4179; outside — metallic zinc not less than 200 g/m² and bituminous varnish; for sewer networks to EN 598 the lining is made of high-alumina cement. The joint is a T-type (Tyton) socket with an EPDM gasket. Every pipe passes a works hydrostatic test: for K9 this is 5.0 MPa at DN80–DN300, 4.0 MPa at DN350–DN600, 3.2 MPa at DN700–DN1000, 2.5 MPa at DN1100–DN1200.
During inspection at the plant the bureau measures the spigot outside diameter with a circumferential tape, wall thickness at the end face with a calliper, thickness along the barrel with an ultrasonic thickness gauge, cement lining thickness at control points; checks the socket and sealing groove, the cast marking — plant mark, DN, class, year — and matches the heat number on the pipe with the plant's mill test certificate (MTC): heat chemistry, mechanical properties, hydrostatic test result. The full set of gaskets and lubricant and the stacking of pipes on bearers before loading are checked separately.
Applications
- trunk water mains and distribution networks of water utilities
- pressure sewers and collectors in the EN 598 version
- industrial water mains and recirculating water supply of plants
- pumping stations, water intakes and reservoir pipework
- irrigation mains of agricultural complexes
- external fire-fighting water supply
Packing and shipment
Pipes are stacked on timber bearers with sockets alternating in opposite directions; DN80–DN300 in strapped bundles. Sealing gaskets and lubricant are packed separately in bags tagged by DN and batch number.
Grade equivalents
| GOST | GB (China) | ASTM | EN | Note |
|---|---|---|---|---|
| VCh45 (GOST 7293-85) | QT450-10 (GB/T 1348) | 65-45-12 (ASTM A536) | EN-GJS-450-10 (EN 1563) | Nearest equivalents by strength and elongation. Pipe standards specify mechanical properties directly; the casting grade in the plant certificate is for reference. |
| K9 (GOST ISO 2531-2012) | K9 (GB/T 13295) | — | K9 (EN 545:2006) | Wall thickness class: e = 9·(0.5 + 0.001·DN), not less than 6 mm. In the ISO 2531:2009 and EN 545:2010 editions pressure classification became the primary one, K9 is retained for continuity. AWWA C151 classifies by pressure; the thicknesses do not match. |
| C40 (GOST ISO 2531-2012) | C40 (GB/T 13295-2019) | — | C40 (EN 545:2010) | Class by allowable operating pressure of 40 bar. At the same DN the C40 wall is thinner than K9; the classes are not equated — the specification names one class and one edition of the standard. |
| Socket with rubber ring (GOST ISO 2531-2012) | Socket T-type (GB/T 13295) | Push-on (AWWA C111/A21.11) | Tyton / push-on (EN 545) | Tyton is a trade name of the joint. Socket seating dimensions are set by the standard, but the groove and gasket profile differs between plants: gaskets are ordered from the pipe manufacturer. |
| — | GB/T 21873 | — | EN 681-1 / ISO 4633 | EPDM sealing gaskets for drinking water. Gasket requirements are checked against EN 681-1 and ISO 4633, which GOST ISO 2531-2012 references. |
| — | GB/T 17457 | AWWA C104/A21.4 | ISO 4179 / EN 545 | Cement mortar lining. Nominal thickness to ISO 4179: 3 mm for DN80–DN300, 5 mm for DN350–DN600, 6 mm for DN700–DN1200. |
| GOST 33259-2015 (PN10, PN16) | GB/T 17241.6 | ASME B16.1 (Class 125) | EN 1092-2 (PN10, PN16, PN25) | Flange connection dimensions PN10 and PN16 to EN 1092-2 and GOST 33259 coincide for most DN and are checked against the drawing. ASME B16.1 has a different bolt-hole pattern and does not mate with EN flanges. |
Equivalents are the closest match, not identical: chemistry and tolerances differ between standards. The exact grade and standard are written into the contract.
Related items
Buyer questions
What to check in the plant's mill test certificate (MTC) for ductile iron pipes
Heat and batch number — the same on the pipe and in the certificate; standard and class (K9 or C40) — the same as in the contract; mechanical properties: tensile strength not less than 420 MPa, elongation not less than 10 %, hardness not more than 230 HB; the result of the works hydrostatic test of each pipe; cement mortar lining thickness and zinc weight per square metre; type and material of the sealing gasket. A certificate without a heat number or with a different edition of the standard is returned to the plant before shipment.
How class K9 differs from C40 and what to write in the specification
K is a wall thickness class: e = K·(0.5 + 0.001·DN); for K9 and DN300 that is 7.2 mm. C is a class by allowable operating pressure in bar: a C40 pipe is rated for 40 bar, the wall is calculated from the pressure and at the same DN comes out thinner than K9. Both systems run in parallel in the ISO 2531:2009 and EN 545:2010 editions. In the specification name one class and one edition of the standard — thickness, weight and the works test of the batch are derived from them.
How the weight and volume of a batch are calculated
Ductile iron pipes are counted in pieces and metres; weight is taken from the standard's table for the class — barrel weight per metre plus socket weight — not from the steel-product formula, since the density of cast iron is 7.05 g/cm³. Fittings are counted in pieces per the schedule, weight per the plant catalogue. For transport the volume is calculated: the number of packages and the transport depend on DN and length, not on tonnage alone. The batch is sized to your volume — send us a specification with DN, class, length, joint type and coatings.
What the bureau's inspector checks at the plant before shipment
The spigot outside diameter with a circumferential tape, wall thickness at the end face with a calliper, thickness along the barrel with an ultrasonic thickness gauge; cement lining thickness and absence of cracks and delamination; the socket and sealing groove; the cast marking — plant mark, DN, class, year; the heat number on the pipe against the certificate; the full set of gaskets and lubricant; stacking on bearers before loading. The result is an inspection report with photographs.
Are pipes and fittings from different plants compatible
In connection dimensions — yes: the spigot outside diameter and socket seating dimensions are set by the standard, flanges to EN 1092-2. In the sealing gasket — no: each plant has its own groove and gasket profile, and another plant's gasket does not fit the socket. The bureau orders pipes, fittings and gaskets from one manufacturing plant or agrees compatibility with the plants in writing before the contract.
Price request
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Steel pricing depends on grade, size, tonnage and delivery terms on the day of contract. A number on the page would be wrong by the time you read it.
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