Composite Manhole Cover vs Cast Iron Manhole Cover

What is a composite manhole cover?

The composite manhole cover is made of fibre reinforced thermosetting composite material with unsaturated polyester resin as the matrix, also known as doughnut moulding compound (DMC), made by compression moulding technology, which is a new type of environmentally friendly cover. The composite manhole cover adopts high temperature and high pressure one-off moulding technology, with high polymerisation and high density, good impact resistance and tensile strength, with the advantages of wear resistance, corrosion resistance, no rusting, no pollution and maintenance free.

The Features of Composite Manhole Cover

1. Active anti-theft properties. No recycling value of the material.

   
   

2. The composite manhole cover has better insulating properties, the resin material fibres are not easily cracked and the toughness is better.

   
   

3. The shapes of the manhole cover are very beautiful. This kind of manhole cover customization is more selective, because the surface of the manhole cover can be customized many patterns. Otherwise, the service life of composite manhole cover is also relatively long.

What is a cast iron manhole cover?

Cast iron manhole covers are divided into ductile iron manhole covers and grey cast iron manhole covers, generally speaking, the same weight of ductile iron manhole covers are stronger than grey iron manhole covers. The material used for grey iron manhole covers is generally HT200, while the material used for ductile iron manhole covers is generally QT500-7.

Cast iron manhole covers are mainly made of ductile iron and the quality of these covers involves the issue of spheroidisation rate. The common coating used to treat the castings is anti-rust asphalt paint, and the surface of the ductile iron manhole covers is also treated with anti-rust asphalt paint.

The Features of Cast Iron Manhole Cover

1. High strength. The tensile strength of ductile iron is further than 420Mpa and the yield strength is further than 300MPa, which is same which is the same with low- carbon sword and three times further than slate iron.

   
   

2. Good durability. Impact value is analogous to carbon sword and 10 times that grey iron.

   
   

3. Good malleability. Extension of ductile is further than 7 which is analogous to high- carbon sword, slate iron material and extend rate is zero.

   
   

4. Anti-corrosion resistance. The erosion was only0.25 times of pipes during ninety days spot erosion test and0.1 times of slate iron pipes. The life is 2 times longer than slate iron pipes and 5 times longer than ordinary sword pipes.

In utmost external operations, similar as water, saltwater, brume, the erosion resistance and oxidation resistance of cast iron are further than sword. Because of the globular graphite cast iron microstructure, ductile iron does better than sword in reduced vibration capacity.

What are the differences between the composite manhole cover and cast iron manhole cover？

• The difference in materials

  Composite manhole cover: belongs to composite material.

  Cast iron manhole cover: belongs to iron material. The force is stronger than resin.

  
  

• The difference in moulding methods

  Composite manhole cover: compression molding. The smoothness is stronger than that of cast iron.

  Cast iron manhole cover: molten iron is cast into shape.

  
  

• The difference in field recognition

  Composite manhole cover: anti-theft, strong acid and alkali resistance. Withstand the wind and sun. The useful life is basically 20-50 years.

  Cast iron manhole cover: easy to be stolen, not resistant to acid and alkali, and the normal service life is 5-10 years.