Ductile iron pipes lined with PU and cement mortar are two common types of corrosion linings, differing primarily in their lining materials, performance characteristics, and application scenarios. Both serve a core purpose: protecting the pipe from corrosion from the media being transported and ensuring water/fluid quality. The following details the differences between these two coated ductile iron pipe.
Main Application:
- Cement coated ductile iron pipe: Mainly used for raw water, drinking water, low-pressure sewage pipes;
- PU coated ductile iron pipe: Corrosive sewage, seawater desalination, industrial wastewater, high flow rate transportation;
Anti-Corrosion Mechanism:
- Ductile iron pipe cement coating: High alkaline passivation film and physical isolation;
- Ductile iron pipe polyurethane coating: Dense coating and chemical inertness, zero penetration;
Surface Properties:
- Cement coated ductile iron pipe: Roughness coefficient K≈0.03mm, easy to scale;
- PU coated ductile iron pipe: Smooth surface, roughness coefficient K＜0.01mm, no scaling, small hydraulic loss;
Abrasion/Impact Resistance:
- Cement coated ductile iron pipe: Generally, easily washed by solid particles;
- PU coated ductile iron pipe：Extremely high, can transport media containing sand and slag;
Temperature Adaptability:
- Cement coated ductile iron pipe：0 – 80℃；
- Polyurethane Coating and Lining on Ductile Iron Pipe: -40 – 120℃；
Sanitary Grade:
- Cement coated ductile iron pipe: Comply with drinking water standards;
- PU coated ductile iron pipe: Solvent-free, VOC-free, NSF/WRAS certified, and can be used for direct drinking water;
Service Life:
- Cement coated ductile iron pipe: ≥50 years;
- PU coated ductile iron pipe: ≥100 years and longer maintenance-free period;
Overall Cost:
- Cement coated ductile iron pipe: Low cost and easy to construct;
- PU coated ductile iron pipe: High cost but low life cycle cost;
Cement lining is economical and versatile, suitable for conventional water supply; PU lining “zero permeability + high wear resistance” is the first choice for high corrosion, high flow rate and long life scenarios. Please contact us for more information on how to choose the right DI pipe.
Post time: Aug-12-2025
