400*500*20, Common Wuhan round square heavy-duty manhole cover in South, usually 60KG-90KG, Northern regions, 400*600B125, Ductile iron manhole covers standard size, suitable for load-bearing and environmental use. Φ symbolizes the diameter. The waterway casting of the ductile iron manhole cover 600 ranges from 60 tons to 5 tons. Ductile iron is obtained by spheroidization and孕育 treatment to form spheroidal graphite, with the national standard being 700: GB/T23858-2009 manhole cover * 700B125.

700cm thick round cast iron manhole covers, the covers produced vary according to different user needs; this depends on the north-south differences. The 500*500 B125, the part fixed to the manhole opening of the inspection well. Optional in standard specifications and sizes, water, and customized with Ductile Iron Manhole Covers, 700*800.