Characteristics of Ductile Iron Manhole Covers

1. High Strength

   Tensile Strength: Ductile iron manhole covers exhibit high tensile strength, typically reaching or exceeding 420 MPa. This is attributed to the unique spherical graphite structure that enhances the mechanical properties of the material. Such high strength allows these manhole covers to withstand significant pressure and load, making them particularly suitable for areas with heavy vehicle traffic, such as urban main roads and highways.

   Yield Strength: The yield strength of ductile iron is also remarkably high, at least 40 MPa, comparable to or even surpassing some cast steel materials. High yield strength means that the manhole cover is less prone to plastic deformation when subjected to external forces, thereby ensuring its structural stability and safety.

2. Excellent Toughness

   Impact Resistance: Ductile iron manhole covers have good toughness, with impact resistance values similar to medium carbon steel, far surpassing those of traditional grey cast iron. This excellent toughness ensures that the manhole cover is not easily broken or deformed upon impact, enhancing its durability and safety.

   Elongation: The elongation rate of ductile iron is relatively high, usually exceeding 7%. This means that the manhole cover can undergo a certain amount of plastic deformation under external forces without easily breaking.

3. Good Corrosion Resistance

   Strong Corrosion Resistance: Ductile iron manhole covers experience minimal degradation under corrosive conditions, leading to a long service life. The surface undergoes special treatment, providing good corrosion resistance, and the dense internal structure prevents corrosion and damage. This allows ductile iron manhole covers to maintain stable performance even in harsh environments such as humidity, acidic, or alkaline conditions.

   Long Service Life: Due to its excellent corrosion resistance, the service life of ductile iron manhole covers is typically long, often exceeding 50 years, reducing the frequency and cost of replacement and maintenance.

4. Stable Quality  

   Precise Production Control: The production process of ductile iron manhole covers is meticulously controlled, utilizing advanced nodulization techniques and intelligent control systems to ensure the stability and consistency of product quality in each batch.

   Anti-Theft Design: Some ductile iron manhole covers incorporate anti-theft designs, such as high-strength bolt connections or integrated designs between the cover and frame, enhancing the manhole cover’s theft-resistant properties.

5. Other Features

   Good Anti-Slip Properties: The surface of ductile iron manhole covers is typically designed with raised edges or anti-slip patterns, increasing friction and enhancing anti-slip performance to prevent slips for pedestrians and vehicles in wet weather conditions.

   Aesthetic Appeal: Ductile iron manhole covers can be customized with surface treatments such as black asphalt coating, making the product look bright and clean, contributing to the beautification of urban environments.

   Eco-Friendly and Energy Efficient: The materials used in ductile iron manhole covers are recyclable, and the manufacturing process is relatively energy-efficient and environmentally friendly, in line with national environmental policies.

In summary, ductile iron manhole covers are widely used in urban construction, roads, streets, and other settings due to their high strength, excellent toughness, good corrosion resistance, stable quality, and features such as anti-slip, aesthetic appeal, and environmental friendliness.