We mainly compare the differences between cast iron manhole covers and ductile iron manhole covers by smelting methods, bearing capacity, strength and toughness, plasticity, corrosion resistance and anti-theft performance.
1. Smelting methods
Cast iron manhole cover is the pig iron directly melted into hot metal, and then cast into the manhole cover.
Ductile iron manhole covers are made by adding inoculants, spheroidizers and rare earth magnesium to gray iron to increase its strength and improve its performance.
2. Bearing capacity
The bearing capacity of cast iron manhole covers is far less than that of ductile iron manhole covers
3. Strength and toughness
The impact resistance value, tensile strength and yield strength of cast iron manhole covers are quite different from those of ductile iron manhole covers.
4. Plasticity
The elongation of ductile iron manhole covers is ≥7%, while the elongation of cast iron manhole covers is almost zero.
5. Corrosion resistance
Ductile iron manhole covers have good corrosion resistance and can be used in harsh environments.
Cast iron manhole covers are easily corroded by rainwater, acid rain and other chemicals, causing rust and corrosion, which seriously affects their service life.
6. Anti-theft performance
The design of ductile iron manhole covers also takes anti-theft performance into consideration, adopting bolt connection and integrated design to reduce the risk of theft.
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