Ductile cast iron manhole covers

Ductile cast iron manhole covers are mainly made of ductile cast iron.  

Ductile iron manhole cover has these advantages:

because of the high strength and good toughness of ductile iron, the ductile iron manhole cover is about 30% lighter than the gray cast iron manhole cover of the same type.  

Characteristics of ductile iron manhole cover:  

① Good toughness.  

The impact value is more than 10 times that of gray iron material.

② Strong corrosion resistance.  

Water spray corrosion test, 90 days corrosion is only 1/40 of steel pipe, is 1/10 of gray iron pipe.  The service life is 2 times than that of gray iron pipe and 5 times than that of ordinary steel pipe.  

③ Good plasticity. 

longation ≥7%, similar to high carbon steel. But gray iron material elongation is about zero.  

④ High strength. 

 Tensile strength OB ≥420MPa, yield strength OS ≥300MPa, is three times of gray iron material.