China As3996 Class D Square Watertight Manhole Cover

about ductile iron (Nodular iron)
Ductile iron, or nodular iron, obtains its special properties through the addition of magnesium into the alloy. The presence of magnesium causes the graphite to form in a spheroid shape as opposed to the flakes of gray iron. Composition control is very important in the manufacturing process. Small amounts of impurities such as sulfur and oxygen react with the magnesium, affecting the shape of the graphite molecules. Different grades of ductile iron are formed by manipulating the microcrystalline structure around the graphite spheroid. This is achieved through the casting process, or through heat treatment, as a downstream processing step.
Product feature
Name
Ductile manhole cover
Material
Ductile iron GGG50/7, gray iron
Standard
EN124/1433/1563
Class
A15,B125,C250,D400,E600,F900
Shape
Round, square, rectangle
Size
200mm-1200mm or as per customers'drawing
Surface
Bituminous black
Molding
DISA Line, Hand Modelling
Process
Drawing-mould making-rawcasting-sand blasting-rough machining-surface treatment-product inspection
Advanced technology and equipments
Tensile strength: 500Mpa Yield stress: 320Mpa
Elongation rate: 7%
Hardness: HBS170-230
Load capacity
B125 C250 D400 E600 F900
Tolerance
Machining:+/-0.2mm, finishmachining:0.2mm
Application
Footway, car parks, main road, aircraftpavements
Advantage
Longevity corrosion resistance,excellent anti-pressure