Microstructure consists of graphite in the form of flakes which act as stress raisers.
Microstructure consists of graphite in the form of spheroids acts like crack arrestors.
Impact resistance is poor. Under severe impact it will break.
Strong impact resistance. Under sevre impact it will bend.
- Tensile strength is low
- No elongation or Ductility
- ISO 185 : 1985 Grade : 350 (Grey Cast Iron).
- Tensile Strength: 350 N / mm2 Min.
- Elongation : Nil.
- Tensile strength is high
- Almost twice than cast iron
- Moderate elongation & ductility
- ISO 1083 : 1987 Grde : 500/7
- Tensile Strength : 500 N / mm2 Min.
- Elongation : 7% Min.
Due to lower strength, weight of the manhole covers will be more for a specfic duty.
Due to high strength, weight of the manhole covers will be less (Min. 2/3rd) by weight.
Due to higher weight handling will be difficult.
Dut to low weight transportation, handling, installation and inspection is easy.
Poor capability of vibration absorption.
High capability of vibration absorption.