Ductile iron manhole cover

Nodular cast iron manhole cover is a kind of nodular cast iron product. Nodular graphite cast iron obtains spheroidal graphite through spheroidization and inoculation treatment, which improves the mechanical properties of cast iron, especially the plasticity and toughness, thereby obtaining higher strength than carbon steel. Nodular cast iron is a high-strength cast iron material developed in the 1950s. Its comprehensive properties are close to steel. It is based on its excellent properties that it has been successfully used for casting complex forces, strength, toughness, and wear resistance. More demanding parts. Nodular cast iron has rapidly developed into a cast iron material second only to gray cast iron and widely used. The so-called "substituting iron for steel" mainly refers to ductile iron.

　　 ductile iron manhole covers are generally divided into round and square. For road administration in urban areas, round is generally used, because round manhole covers are not easy to tilt and can better protect pedestrians and vehicles. The use of circular shape is mainly considering that the length of each diameter of the round manhole cover passing through its center is the same, so that if the manhole cover is rolled up by a passing vehicle, because no matter how it is rolled up, its diameter will be slightly smaller than that of the wellhead below. Wide, the manhole cover will not fall into the wellhead.

　　 If a square is used, because the diagonal of the square is obviously longer than the length of each side, when such a manhole cover is rolled up, it is easy to fall into the well along the diagonal direction of the wellhead, causing safety hazards. If the well head is round or significantly smaller than the well cover, the square well cover will not fall into the well. This involves the issue of large-scale utilization and saving of materials. The use of the manhole cover depends on the size of the wellhead. If a square manhole cover with a much larger area than the wellhead must be installed on it, the material utilization and practical value are naturally not directly used for the round manhole cover, which saves the material of the manhole cover and also Ensure the safety of the wellhead.

　　In the countryside and cable wells, they are generally square, which can better prevent rainwater and other liquids from entering.