The Class K12 DN450 Ductile Iron Pipe delivers a robust, long-term solution for medium- to high-pressure water, sewage, and industrial networks. Engineered to ISO 2531/EN 545 standards, its K12 thickness class sustains operating pressures up to 16 bar while accommodating angular deflections during ground movement. The nominal DN450 (Ø 450 mm) size strikes a balance between large flow capacity and manageable handling, making it ideal for both urban distribution and rural irrigation schemes. With cement‐mortar internal lining (ISO 4179) and zinc/bitumen or epoxy external coatings (ISO 8179), these pipes resist corrosion in aggressive soils, ensuring an expected service life beyond 100 years under normal conditions. Installation leverages push-on or restrained K-type mechanical joints for rapid, leak-free assembly without special bedding. Competitive pricing—US $439–558 per ton for K12 class—positions DN450 pipes as a cost-effective choice when life-cycle costs are considered.
Application Scenarios
Ductile iron DN450 K12 pipes are extensively used in municipal water-supply networks, where they transport potable water under pressures up to 16 bar in compliance with BS EN 545. Their high safety factor and resilience to ground settlement make them suitable for sewerage and pressure-sewer systems, conforming to BS EN 598, and for agricultural irrigation, where long-term durability and minimal downtime are critical. In industrial and power facilities, DN450 pipes serve cooling-water circuits, mine-dewatering lines, and chemical-process feeds, benefiting from ductile iron’s superior tensile strength (≥ 270 MPa) and elongation (≥ 7 %) characteristics.
Service Life & Durability
Modern ductile iron pipes deliver 100+ years of service under typical operating conditions, as validated by manufacturer warranties and field data. The cement-mortar lining (ISO 4179) prevents internal corrosion, while zinc bitumen or epoxy-ceramic coatings (ISO 8179) protect against external chemical attack. In highly aggressive soils, polyethylene sleeving per ANSI/AWWA C105/A21.5 adds another layer of defense, virtually eliminating pitting and extending lifespan beyond a century .
Laying & Connection
Mechanical K-Type Joints
Class K12 pipes incorporate integral sockets with resilient SBR/NBR/EPDM gaskets, allowing push-on assembly with no flange bolts. This “Tyton” or K-Type joint enables ±5° angular deflection per joint to absorb ground movements and reduces installation time by up to 30 % compared to flanged systems.
Restrained & Flanged Options
For thrust-resistant installations (e.g., steep grades, anchor blocks), restrained-joint variants lock the spigot to the socket via cast-on lugs and mechanical restraints (EN 545). Flanged ends to EN 1092-2 can be specified for above-ground or maintenance-intensive settings, ensuring rapid removal and replacement of segments.
Compliance with International Standards
Class K12 DN450 pipes adhere to:
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ISO 2531 (ductile iron pipes, fittings, accessories)
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EN 545 (water pipelines) and EN 598 (sewerage)
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ISO 4179 (cement-mortar lining) and ISO 8179 (external coatings)
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ISO 9001-certified manufacturing, with pressure & deflection tests at 1.5× PN rating .
Price Comparison with Other Series
| Thickness Class | Price Range (USD/ton) | Source |
|---|---|---|
| K7 | 600 (1–24 t), 500 (25–99 t), 400 (100 t+) | alibaba |
| K9 | 600 (1–24 t), 500 (25–99 t), 400 (100 t+) | alibaba |
| K12 (DN450) | 439 – 558 (1 t FOB Tianjin) | alibaba |
| C25 | 600 (1–24 t), 500 (25–99 t), 400 (100 t+) | alibaba |
| C40 | 600 (1–24 t), 500 (25–99 t), 400 (100 t+) | alibaba |
Key Advantages
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High Pressure Capability: PN 16 rating for reliable delivery in large networks
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Superior Ductility & Strength: GGG50 iron with Rp0.2 ≥ 270 MPa and A ≥ 7 %
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Exceptional Corrosion Resistance: Multi-layer linings & coatings plus PE sleeving options
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Ease of Installation: Push-on mechanical joints reduce labor and trenching time
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Low Life-Cycle Cost: Minimal maintenance and long service life offset initial investment
Frequently Asked Questions
Q1: What pressures can K12 DN450 handle?
Up to 16 bar (PN 16) at ambient temperatures; hydrostatic testing at 1.5× PN confirms integrity.
Q2: How do I choose between push-on and restrained joints?
Use push-on for straight runs in stable soils; choose restrained or flanged when seismic activity, high thrust, or maintenance access are concerns.
Q3: Are all joint gaskets compatible with potable water?
Yes—EPDM/SBR/NBR gaskets comply with WRAS, NSF 61, and other potable-water approvals.
Case Studies
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Central Arkansas Water (USA): Switched to ductile iron for new DN450 sections, reporting ease of assembly (bell & spigot, mechanical, flanged), pressure tests to 225 psi, and minimal handling damage versus PVC/HDPE .
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Arizona Water Service Utilities: Prohibited PVC in urban networks and standardized on ductile iron, citing long-term reliability and reduced leak incidents.
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EPD International (2025): Documented DN450 use in potable, industrial, irrigation, and pressure-sewer applications, highlighting environmental benefits and recyclability.
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 | ….. |
