The water grate of ductile iron is mainly made of ductile iron.It is also treated with anti-rust asphalt paint.Ductile iron manhole covers have one advantage,That is  the ductile iron’s strength high and toughness is very good,So The ductile cast manhole cover is about 30% lighter than the same type of gray cast iron manhole cover. Ductile grating’s application: Municipal road drainage, water collection …