Ductile Iron vs Cast Iron Manhole Covers — Which to Choose?

What is a Ductile Iron Manhole Cover?

Ductile iron (also known as spheroidal graphite iron or SG iron) is a type of cast iron treated with magnesium to change the graphite structure from flakes to spheroids, dramatically improving mechanical properties.

Ductile Iron vs Cast Iron: Key Differences

| Property | Cast Iron | Ductile Iron | |---------|-----------|-------------| | Tensile strength | 150-300 MPa | 350-700 MPa | | Elongation | <1% | 6-22% | | Impact resistance | Low | High | | Brittleness | High | Low | | Cost | Lower | Higher |

When to Choose Ductile Iron

• High-traffic roads and highways (D400 and above)
• Areas with heavy goods vehicles
• Airports and dock areas (E600)
• Locations where impact resistance is critical

Advantages of Ductile Iron Covers

1. Higher strength-to-weight ratio: 20-30% lighter than equivalent cast iron
2. Impact resistance: Absorbs energy without cracking
3. Longer service life: Improved mechanical properties
4. Better security: Locking mechanisms more effective
5. Reduced noise: Less rattle under traffic loads

Contact HAMS Engineering

📞 +94 76 066 0861 | 📧 info@hhkplumbing.com