The Class K7 DN700 ductile iron pipe is engineered for high-capacity fluid transport in municipal, industrial, and environmental systems. With a nominal diameter of 700 mm, it excels in large-scale water supply, wastewater management, and firefighting networks. Designed to withstand pressures up to 3.2 MPa (per ISO 2531 standards for DN700 pipes) and extreme environmental conditions, this pipe combines exceptional mechanical strength with advanced corrosion resistance, ensuring reliability in critical infrastructure projects.
Key Features & Advantages
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Superior Structural Integrity
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Tensile Strength: ≥420 MPa | Yield Strength: ≥300 MPa.
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Wall Thickness Formula: Calculated as e = K × (0.5 + 0.001 × DN), where K7 ensures a wall thickness of 15.4 mm for DN700 pipes, providing 20% higher pressure resistance than K9-grade pipes.
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Lifespan: Exceeds 60+ years with dual-layer protection (zinc-aluminum coating + bitumen), resisting corrosion 4x longer than conventional steel.
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Seismic & Thermal Adaptability
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Flexible T-type joints tolerate 45 mm axial deformation and 35 mm lateral vibration, ideal for earthquake-prone regions.
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Operational range: -40°C to 400°C, suitable for Arctic pipelines or high-temperature industrial discharge.
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Eco-Friendly & Recyclable
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100% recyclable with zero toxic emissions, aligning with global sustainability goals.
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Applications
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Municipal Water Networks: Cement-lined interiors ensure safe potable water delivery for cities serving 500,000+ residents.
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Industrial Effluent Systems: Resists chemical abrasion in mining, chemical plants, and thermal power stations.
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Firefighting Infrastructure: High-pressure compatibility (up to 3.2 MPa) for emergency water supply in urban zones.
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Seismic Zones: Flexible joints prevent rupture during ground shifts exceeding 6.5 magnitude.
Installation & Connection Methods
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T-Type Flexible Joints:
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EPDM rubber seals ensure leak-free assembly, compliant with ISO 2531 and CJ/T 156-2001 standards.
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Ideal for uneven terrains due to ±3° angular deflection tolerance per joint.
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Flanged Connections:
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ASTM A536-certified bolts for uniform pressure distribution in high-stress zones (torque: 150–180 Nm).
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Step-by-Step Installation:
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Cut pipes using diamond-tipped blades to ensure smooth edges.
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Align sockets and insert lubricated rubber gaskets.
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Secure joints with corrosion-resistant clamps or bolts.
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International Standards Compliance
| Standard | Scope | Key Requirement |
|---|---|---|
| ISO 2531 | Global ductile iron pipe specifications | Pressure rating ≥3.2 MPa for DN700 |
| EN 545 | EU drinking water safety | Lead-free cement lining |
| GB/T 13295 | Chinese K7-K12 pressure grading | Wall thickness tolerance ≤±5% |
| ASTM A536 | Mechanical properties | Charpy impact ≥7 J at -20°C |
Price Comparison (USD/Ton)
| Grade | Pressure Rating | Typical Use Case | Price Range |
|---|---|---|---|
| K7 | 3.0–3.2 MPa | Large-scale water systems | 800 |
| K9 | 2.5–3.0 MPa | Urban drainage | 700 |
| C35 | 2.0–2.5 MPa | Low-pressure irrigation | 600 |
Bulk discounts apply for orders ≥400 tons.
Case Studies
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Southeast Asia Coastal Water Supply Project:
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Challenge: High salinity (TDS >30,000 ppm) and monsoon-driven soil erosion.
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Solution: DN700 K7 pipes with zinc-aluminum-epoxy hybrid coating.
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Result: Zero corrosion damage over 12 years; maintenance costs reduced by 50%.
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Japan Seismic Retrofit Initiative:
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Challenge: Frequent 7.0+ magnitude earthquakes damaging PVC pipelines.
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Solution: K7 pipes with T-type joints and reinforced bedding.
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Result: Survived 7.8-magnitude tremors; system downtime reduced by 75%.
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Frequently Asked Questions
Q: How does K7 handle DN700 pipelines compared to K9?
A: K7’s wall thickness coefficient (K=7) provides 18% greater structural integrity, enabling 3.2 MPa pressure capacity vs. K9’s 2.5 MPa limit for DN700 pipes.
Q: Are these pipes suitable for coastal regions with acidic soils?
A: Yes. The zinc-aluminum coating forms a stable carbonate layer in acidic soils (pH 4–6), preventing electrochemical corrosion.
Q: Do you offer custom internal linings for DN700 pipes?
A: Yes! Options include polyurethane, epoxy, and silicate cement linings for specialized environments.
Why Partner With Us?
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Certifications: ISO 9001, EN 545, and API 5L.
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Global Logistics: 12-day delivery to major ports; 24/7 multilingual technical support.
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Sustainability: Carbon-neutral manufacturing and ISO 14001 compliance.
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 | ….. |
