With the rapid development of China's economy, China's infrastructure construction and investment have ushered in a new cycle. Manhole covers are in great demand in urban planning and road construction. The data used in manhole covers are mostly reinforced concrete raw materials, which are cast due to defects such as large brittleness, simple aging, and easy fracture, and have been replaced by materials such as cast iron and stainless steel.
With the continuous and rapid development of China's economy, manhole covers have been used more and more widely in urban planning and road construction. This indicates the bulging of a new type of stainless steel manhole cover anti-theft door industry. The stainless steel manhole cover can be used in various conditions instead of the cast iron manhole cover . The stainless steel manhole cover has further improved functions and increased promotion. Its spring has now come.
1. Cast iron manhole covers are available in gray cast iron and ductile iron:
① Gray cast iron manhole cover: It has certain carrying capacity, and is cheap, brittle, easy to rust, and easy to be stolen. Stainless steel manhole covers are mainly used in some non-load bearing areas and residential quarters.
② Ductile iron manhole cover: Compared with the gray cast iron manhole cover, the bearing capacity can be improved, and the toughness of the material is relatively difficult to rust. However, the price has increased significantly. Similarly, because of its recovery value, it is easy to be stolen, and it is mainly used on roads and roadsides with loads. In order to deal with the anti-theft problem, many anti-theft manhole covers with locks have been developed. Although the anti-theft problem has been dealt with to this extent, it has made it difficult to open the manhole cover and the cost has further increased, bringing economic and operational benefits to users Difficulties.
2. Cement manhole cover Cement manhole cover is filled with high grade cement in steel frame or mixed with steel hoop or steel fiber in cement, which has strong rigidity, brittleness, resistance to acid and alkali corrosion, easy ageing and easy fracture. Stone manhole covers made of some ore, terrazzo, etc. can only be used in limited localities because of product raw materials.
3． FRP manhole cover FRP manhole cover has been taken seriously because it has no recovery value, it can handle the anti-theft problem very well, and stainless steel manhole cover has good load ability. However, the high cost of FRP manhole covers can only make malls less competitive. In addition, the FRP manhole cover is flexible, and the bearing capacity is inferior to that of the cast iron manhole cover. If the self-weight is not good, it may cause the car to rebound and roll over. Therefore, the amount and scope of use of FRP manhole covers are small.
4. Stainless steel manhole cover While stainless steel manhole cover does not add any auxiliary raw materials, stainless steel manhole cover directly smelts pig iron into molten iron and then pours it into a manhole cover. However, nodular cast iron manhole covers are made by adding nodulizing agent, rare earth magnesium and other metal alloys.