What does C250 on the nodular well cover mean and what does it mean?
Nodular well cover is a kind of nodular cast iron. Nodular graphite is obtained from nodular cast iron through spheroidization and inoculation, which effectively improves the mechanical properties of cast iron, especially the plasticity and toughness, so as to obtain 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. Based on its excellent properties, it has been successfully used to cast some parts with complex stress and high requirements for strength, toughness and wear resistance. Nodular cast iron has rapidly developed into a widely used cast iron material second only to gray cast iron. The so-called "replacing steel with iron" mainly refers to nodular cast iron.
What is the meaning of C250 in nodular cast iron manhole cover?
Nodular cast iron manhole cover C250 refers to the manhole cover with a load of about 25 tons, and the nodular cast iron manhole cover with an experimental load of 250kN (KN). According to industry standards, this rainwater well cover is used on the motorway of the secondary trunk road.
Nodular cast iron manhole covers are generally divided into round and square. In terms of urban road administration, circular manhole covers are generally used, because circular manhole covers are not easy to tilt, which can better protect the safety of pedestrians and vehicles. The use of circular covers mainly takes into account that the length of each diameter of the circular well cover passing through its center is the same. In this way, if the well cover is rolled up by passing vehicles, no matter how it is rolled up, its diameter will be slightly wider than the wellhead below, and the well cover will not fall into the wellhead.
If the square is used, because the diagonal of the square is obviously longer than the length of each side, when the well cover is rolled up, it is easy to fall into the well along the diagonal direction of the wellhead, resulting in potential safety hazards. If the wellhead is round or significantly smaller than the well cover, the square well cover will not fall into the well. This involves the problem of maximum utilization and saving of materials. The use of the wellhead depends on the size of the wellhead. If it is necessary to install a square well cover with an area much larger than the wellhead, the utilization and practical value of the material is naturally more effective than using the circular well cover directly, which not only saves the material of the well cover, but also ensures the safety of the wellhead. In rural areas and cable wells, square is generally used, which can better prevent the entry of rainwater and other liquids.