The cover of spheroidal graphite cast iron is mainly made of spheroidal graphite cast iron. The quality of this kind of well cover is involved in the problem of the rate of spheroidization. The commonly used coatings for castings are anticorrosive asphalt lacquer, and of course the surface of the ductile iron cover is also treated by spraying antirust bitumen lacquer. The advantage of ductile iron well covers is that the strength of ductile iron covers is about 30% lighter than that of the same type of gray iron covers because of the high ductility and toughness of ductile iron. Guizhou foundry tells you that the cast iron manhole covers on the market refer to the ductile iron manhole covers.
Good toughness and impact value: carbon steel in detail, is more than 10 times the iron material.
Strong corrosion resistance: water spray corrosion test, ninety days of corrosion is only 1/40 of steel pipe, is the 1/10 of the ash iron pipe. The service life is 2 times that of the gray iron pipe and 5 times that of the ordinary steel pipe.
Good plasticity: elongation rate greater than 7%, similar to high carbon steel, and iron material extension rate is zero。
High strength: tensile strength, yield strength, B = 420MPa, s = 300MPa, with the same low carbon steel, is three times the iron material。
Cast iron shaft covers are widely used in municipal roads, expressway, communications, electricity, tap water, residential areas, schools and other parks。
铸铁井盖一般分圆形和方形，铸铁井盖规格尺寸：重型400KN，普型250KN，轻型125KN，方型：500*500 600*600 700*700 450*750等 圆型：600 700 800 900 1000等， 每种规格的重量分很多种，导致承重有所不同。
Cast iron manhole covers generally round and square, cast iron manhole cover size: heavy 400KN, general 250KN, 125KN light, 500*500 600*600 700*700 450*750: a square round type: 6007008009001000, the weight of each specification is divided into many kinds, resulting in different bearing。