Cast iron manhole covers have been used for many years. It can be said that the anti-corrosion performance of cast iron manhole covers must be very good. In order to withstand such a test, his anti-corruption performance must be good. To achieve such an effect, strict treatment must be carried out. It is through asphalt coating. Before painting, pipes are preheated to speed up the adhesion of asphalt and dry it quickly, and aluminum aluminate coating. These two processes are very suitable for anti-corrosion coating. Ball mill well cover is a kind of cast iron, It is made of cast iron and spheroidized to spheroidal graphite, which can effectively improve the performance of cast iron, especially improve the plasticity and toughness of the product, and finally reach a strength higher than that of carbon steel. This is the characteristics of our spheroidal graphite manhole cover. With these characteristics, it will be able to withstand various severe tests.

Ductile iron manhole cover is a manhole cover made of a kind of ductile iron and placed at the mouth of the road sewer. It can bear large loads, and has a firm, stable and durable structure. At the same time, it plays a vital role in the daily maintenance of roads, sewers, optical fiber and other outlets. In addition, its material prices are low, which can meet the market demand and is widely used in the market. From the design point of view, ductile iron manhole covers have good flexibility. It is easy to make square or round manhole covers, and it is also easy to adjust the unqualified products. Its material is also very light, because its density is small, about 30% of the same kind of cast iron, and it can also save a lot of costs in transportation, installation and other links. Therefore, generally speaking, nodular cast iron manhole covers have many advantages in design, cost, maintenance, price and other aspects, and are the best choice in the market.

We should all be familiar with ductile iron manhole covers. We often see manhole covers on the road. They should be indispensable for road administration. It can be imagined that our safety would be greatly affected if there were no manhole covers. The manhole covers we often see should be round and square. Have you ever wondered why they are made of these two shapes instead of other shapes? Does shape have any impact on safety? In terms of road administration in urban areas, the most important factor is that the round manhole cover is not easy to tilt, which can better protect the safety of pedestrians and vehicles. However, if the square is used, because the diagonal of the square is significantly longer than the length of each side, when such a well cover is rolled up, it is easy to fall into the well along the diagonal direction of the wellhead, causing potential safety hazards.

From the use experience, the round nodular graphite manhole cover is more commonly used because it has higher safety. A circle is a shape with the same diameter no matter how it is measured. Therefore, a round manhole cover will not fall down no matter how it is rolled by vehicles because its diameter is wider than the wellhead. This is also the reason why circular manhole covers are used most.

Steel castings are often made in dusty places. There are many dusts in the air, which constantly fall on the surface of the equipment. They can be removed with water or alkaline solution. However, dust with adhesion needs to be cleaned with high-pressure water or steam

2. Floating iron powder or embedded iron on the surface of nodular iron castings
On any surface, free iron will rust and corrode stainless steel. Therefore, it must be removed. Float powder can be removed together with dust. Some have strong adhesion and must be treated as embedded iron.

3. Scratches on spheroidal graphite castings
Scratches and other rough surfaces must be mechanically cleaned in order to prevent the accumulation of process lubricants or products and/or dirt

4. Rust spot of nodular cast iron
Rust is sometimes seen on stainless steel products or equipment before or during fabrication, which indicates that the surface is seriously polluted. Rust must be removed before the equipment is put into use. Thoroughly cleaned surfaces shall be inspected by iron test and/or water test