Class K9 DN450 ductile iron pipe combines optimal strength and durability with ease of installation and long-term cost efficiency. With a nominal wall thickness of approximately 8.55 mm (T = 9 × (0.5 + 0.001 × 450)) and a design pressure of 9 bar, it reliably serves high-pressure water and wastewater systems for 100 + years with minimal maintenance. Its push-on, mechanical, restrained, and ball-and-socket joints, plus trenchless installation options (HDD, microtunneling), allow rapid, flexible deployment in congested or sensitive environments. Priced competitively at USD 460–560 per ton, it strikes the ideal balance between cost and performance compared to Class K7, K8, and K12 alternatives. Fully compliant with ISO 2531, EN 545/598, AWWA C151/A21.51, and related standards, Class K9 DN450 ensures global interoperability and peace of mind .
Application Scenarios
Ductile iron’s mechanical properties and corrosion protection make it ideal for:
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Potable water transmission & distribution (mains, treatment-plant interconnects)
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Wastewater & stormwater conveyance (gravity sewers, drainage, buried applications)
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Industrial & irrigation systems (power plants, refineries, agricultural networks)
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Subaqueous & trenchless crossings via HDD or microtunneling under rivers, highways, and railways
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Sewer rehabilitation when chemical or abrasive sludges are present
Service Life
Modern ductile iron pipe endures over a century with:
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Internal cement-mortar lining resisting corrosion and biofouling
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External zinc-bitumen or polyethylene coatings per ISO 8179 protecting against aggressive soils
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≥ 80 % recycled content and full recyclability for environmental sustainability
Installation and Jointing
Class K9 DN450 supports multiple joint systems:
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Push-on joints for fast, simple assembly without thrust blocks
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Mechanical (Tyton®) & restrained (Tyton SIT PLUS®) joints eliminating concrete thrust blocks
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Boltless ball-and-socket joints permitting angular deflections up to 15° for alignment flexibility
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Trenchless methods (HDD, microtunneling) with tension-locked spigots for minimal surface impact
Product Series Comparison and Pricing
| Class | Design Pressure | Wall Thickness (DN 450) | Price/Ton (USD) | Ideal Use Case |
|---|---|---|---|---|
| K7 | 7 bar | ≈ 6.65 mm | 460–560 | Low-pressure distribution |
| K8 | 8 bar | ≈ 7.60 mm | 460–560 | Medium-pressure mains |
| K9 | 9 bar | ≈ 8.55 mm | 460–560 | Standard high-pressure lines |
| K12 | 12 bar | ≈ 11.40 mm | 460–560 | Transmission & high-head |
(T = K × (0.5 + 0.001 × D), D = 450 mm, K = class)
International Standards
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ISO 2531:2009 / ISO 8180 – Pipes, fittings, accessories.
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EN 545 & EN 598 – Drinking-water and sewer mains.
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AWWA C151/A21.51 & C110/A21.10 – U.S. potable-water applications.
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ISO 4179 – Internal cement-mortar lining.
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ISO 8179 – External protective coatings.
Advantages
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High strength & ductility (tensile ≥ 400 MPa, elongation ≥ 10 %).
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Corrosion resistance via dual linings/coatings for long-term performance.
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Rapid, flexible installation with modular joints and trenchless options.
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Century-plus lifespan supported by extensive field data.
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Lifecycle cost savings through reduced maintenance and energy use.
FAQ
Q1: Can Class K9 pipe withstand seismic events?
A1: Yes—rubber-ring (EPDM) gaskets and restrained-joint designs accommodate ground movement without leakage.
Q2: What coating options exist?
A2: Standard zinc-bitumen; optional polyethylene encasement, epoxy, or polyurethane.
Q3: How are leak-tight joints ensured?
A3: Precision-cast bells, EPDM/SBR gaskets, and restrained systems guarantee a reliable seal.
Q4: Are fittings and valves standardized?
A4: Yes—compatible with ISO 2531, EN 545 dimensions, and AWWA C110 flanges.
Case Studies
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Lafayette, LA HDD crossings: Three successful HDD pulls (1,140 ft, 940 ft, 740 ft) using K9 ductile iron pipe demonstrated minimal disruption, cost savings, and rapid installation.
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Aurora, CO water infrastructure: Aurora Water chose ductile iron for high-cyclic loading zones; the durable pipes met pumping-cycle stresses with zero failures over 15 years.
ductile iron pipe dimensions
| Pipe body weight （kg/m) | |||||||||||||||
| (Inside Diameter) | (Outside Diameter) | Socket Weight | K8 | K9 | K10 | C class | Total weight of Active Length=6M (kg) | Total weight of Active Length=5.7M (kg) | |||||||
| DN(mm) | OD(mm) | ≈ kg | Class | kg/m | K8 | K9 | K10 | C class | K8 | K9 | K10 | C class | |||
| 80 | 98 | 3.40 | 12.20 | 12.20 | 12.20 | C40 | 9.10 | 77.00 | 77.00 | 77.00 | 58.00 | 73.00 | 73.00 | 73.00 | 55.00 |
| 100 | 118 | 4.30 | 14.90 | 15.10 | 15.10 | C40 | 11.12 | 93.70 | 95.00 | 95.00 | 71.00 | 90.00 | 91.00 | 90.00 | 68.00 |
| 125 | 144 | 5.70 | 18.90 | C40 | 119.00 | ||||||||||
| 150 | 170 | 7.10 | 21.80 | 22.80 | 22.80 | C40 | 16.48 | 138.00 | 144.00 | 144.00 | 106.00 | 132.00 | 138.00 | 137.00 | 101.00 |
| 200 | 222 | 10.30 | 28.70 | 30.60 | 30.60 | C40 | 22.62 | 183.00 | 194.00 | 194.00 | 146.00 | 174.00 | 185.00 | 185.00 | 139.00 |
| 250 | 274 | 14.20 | 35.60 | 40.20 | 44.30 | C40 | 32.63 | 228.00 | 255.00 | 280.00 | 210.00 | 218.00 | 244.00 | 267.00 | 200.00 |
| 300 | 326 | 18.90 | 45.30 | 50.80 | 56.30 | C30 | 43.90 | 290.00 | 323.00 | 357.00 | 282.00 | 278.00 | 309.00 | 340.00 | 269.00 |
| 350 | 378 | 23.70 | 55.90 | 63.20 | 69.60 | C30 | 51.88 | 359.00 | 403.00 | 441.00 | 335.00 | 343.00 | 384.00 | 420.00 | 319.00 |
| 400 | 429 | 29.50 | 67.30 | 75.50 | 83.70 | C30 | 60.78 | 433.00 | 482.00 | 532.00 | 394.00 | 414.00 | 460.00 | 506.00 | 376.00 |
| 450 | 480 | 38.30 | 80.00 | 89.30 | 99.00 | C30 | 73.30 | 515.00 | 575.00 | 632.00 | 472.00 | 492.00 | 550.00 | 597.00 | 450.00 |
| 500 | 532 | 42.80 | 92.80 | 104.30 | 115.60 | C30 | 87.20 | 600.00 | 669.00 | 736.00 | 566.00 | 572.00 | 638.00 | 702.00 | 540.00 |
| 600 | 635 | 59.30 | 122.00 | 137.30 | 152.00 | C30 | 120.62 | 791.00 | 882.00 | 971.00 | 783.00 | 755.00 | 842.00 | 926.00 | 747.00 |
| 700 | 738 | 79.10 | 155.00 | 173.90 | 193.00 | C25 | 142.15 | 1009.00 | 1123.00 | 1237.00 | 932.00 | 963.00 | 1071.00 | 1179.00 | 889.00 |
| 800 | 842 | 102.60 | 192.00 | 215.20 | 239.00 | C25 | 177.07 | 1255.00 | 1394.00 | 1537.00 | 1165.00 | 1197.00 | 1330.00 | 1465.00 | 1112.00 |
| 900 | 945 | 129.60 | 232.00 | 260.20 | 289.00 | C25 | 197.68 | 1521.00 | 1691.00 | 1863.00 | 1446.00 | 1452.00 | 1613.00 | 1777.00 | 1257.00 |
| 1000 | 1048 | 161.30 | 275.00 | 309.30 | 343.20 | C25 | 266.28 | 1811.00 | 2017.00 | 2221.00 | 1759.00 | 1729.00 | 1925.00 | 2118.00 | 1679.00 |
| 1100 | 1152 | 194.70 | 362.80 | 2372.00 | |||||||||||
| 1200 | 1255 | 237.70 | 374.00 | 420.10 | 466.10 | C25 | 373.88 | 2482.00 | 2758.00 | 3034.00 | 2481.00 | 2370.00 | 2632.00 | 2894.00 | 2369.00 |
| 1400 | 1462 | 279.30 | 547.20 | 3563.00 | |||||||||||
ductile iron pipe Mechanical property
| Mechanical Property | |||||||
| Nominal Diameter | Hydraulic test | Tensile strength | Elogation | Yield strength | Bending strength | Brinell hardness | Thickness of cement lining |
| DN(MM) | Mpa | Mpa | % | Mpa | Mpa | HB | mm |
| DN80-DN300 | 5 | ≥420 | ≥10 | ≥300 | ≥590 | ≤230 | 3 |
| DN350-DN600 | 4 | ≥420 | ≥10 | ≥300 | ≥590 | ≤230 | 5 |
| DN700-DN1000 | 3.2 | ≥420 | ≥10 | ≥300 | ≥590 | ≤230 | 6 |
| DN1100-DN1600 | 2.5 | ≥420 | ≥7 | ≥300 | ≥590 | ≤230 | ….. |
