Cast iron manhole cover

Cast iron manhole covers have high strength and good toughness, so ductile iron manhole covers are about 30% lighter than gray cast iron manhole covers of the same type. The ductile iron grade is QT500-7, and the temperature of the molten iron is not less than 1456 ℃. During spheroidization treatment, rare earth ferrosilicon magnesium alloy is added and low sulfur coke is selected, with a spheroidization level of three or above. The mechanical properties of ductile iron specimens are as follows:

Tensile strength: 500N/MM 2

Elongation rate: 7%

The pressure test failure load of cast iron manhole cover exceeds the national industry standard;

The adopted standards are as follows:

The standard specified in CJ/T3012-93 "Cast Iron Inspection Manhole Cover"

EN124 "Drain covers and inspection manhole covers for pedestrian walkways in lanes"

The dimensional deviation between the manhole cover and the base complies with national standards

Ductile iron manhole cover: It is used for outdoor manholes inside industrial and civil building areas It can meet the needs of laying road ballast, marble and granite in residential areas. All products can open the cover plate and can be used for water supply and drainage wells, ventilation wells, cable wells, instrument wells, etc. It is composed of a well frame and a well cover. At the same time, its strength and toughness are much higher than cast iron, and it can also be used in environments with large spans and heavy loads such as docks and airports; The new type of invisible manhole cover consists of a well frame and a manhole cover, and the manhole cover is designed with a square groove. Its cross-section can also be an inverted trapezoid, which can make the fit between the manhole cover and the manhole frame more tight, improving the shortcomings of current manhole covers. The invisible manhole cover only exposes the four sides of the frame on the ground surface, and the middle of the manhole cover is concave to a certain depth. The bottom of the concave surface of the cast iron manhole cover is designed as an arc, and there are reinforcing ribs on the concave surface. The lightweight invisible manhole cover is made of steel plate structure and can be directly tiled on the surface.