1.Material:Ductile Iron GGG50 2.Size:780*780 3.Load ... bearing great: the toughness of ductile iron is fourfold that of ordinary cast iron, close to steel materials, suitable for ... internal environment complex, filled with various chemical substances, ductile iron does not suffer chemical corrosion, service life more than ... not depart from the ground. Square Manhole cover,casting cover,Ductile Iron