The ductile iron manhole cover we usually see is made of cast iron flat plate. In order to prevent the cast iron flat plate from deforming, we need to know some methods to maintain the cast iron flat plate. We can maintain the cast iron flat plate from the following aspects to prevent cast iron We can clean the floor when laying the flat board, and then lay waterproof cardboard on it. This is to prevent moisture from affecting the cast iron flat board. Of course, we must ensure the durability and stability of the waterproof board. 2. When the cast iron plate is not used, we need to place it in a relatively dry environment, cover it with rust-proof paper, and ensure that the platform is clean, and do not leave some stains or scratches on the cast iron plate Mark of. 3. We need to regularly inspect the surface of the cast iron slab in accordance with international standards. According to the family regulations, we will conduct a thorough inspection every 8 months or so, so as to ensure its performance and better protect it.
Iron manhole covers have no recycling value. This is because the cast iron manhole covers are made of unsaturated resin, glass fiber and other materials and steel framework, which are compounded by different production processes. The composition of the resin is also divided into natural and synthetic.
The resin of the raw material of cast iron manhole covers is generally considered to be the normal metabolites or secretions of plant tissues. It often coexists with the volatile oil in the secretory cells, resin channels or ducts of plants, especially in the ducts of the heartwood of perennial herbs. A mixture composed of multiple components, usually amorphous solid, slightly shiny, hard and brittle, and a few are semi-solid. It is insoluble in water and does not swell by absorbing water. It is easily soluble in most organic solvents such as alcohol, ether and chloroform. It is softened by heating, and then melted. There will be thick smoke when burned, and there will be other aroma or odor.
The resin used as the raw material for cast iron manhole covers can be divided into two categories: natural resin and synthetic resin. The classification standard of ductile iron manhole covers. Synthetic resin refers to the resin product obtained from simple organic matter through chemical synthesis or chemical reaction of certain natural products. Synthetic resin is an important component of plastics. Natural resin refers to the amorphous organic substances derived from the secretions of animals and plants in nature, such as rosin, amber, shellac, etc.
The manhole cover is generally round, mainly used to cover roads or deep wells in homes to prevent people or objects from falling. As we all know, noise will also occur during the actual use of the manhole cover. How can this be solved? We must first find the source of the noise of the manhole cover, and then remove it in a targeted manner.
In general, a complete manhole cover device is composed of a manhole cover base and a manhole cover. During the application process, due to the rolling of vehicles or heavy objects, the manhole cover base and the manhole cover will loosen and create gaps. As a result, when the manhole cover seat and the manhole cover collide, noise will be generated, which will seriously affect the surrounding environment and residents' lives, and also bring security risks.
In response to this, we can fix a shock-proof rubber ring under the manhole cover device and the wellhead to strengthen the stability of the manhole cover, so that the possibility of noise is greatly reduced, and the manhole cover material can also be improved and improved.
The endothermic pressure is about 1/10 of the melting pressure of the cast iron manhole cover. The main function of the ductile iron manhole cover is to prevent the product from rebounding, make the product stick to the heating plate, improve the heating effect and reduce the heating time. The time of the heating phase is related to the cross-sectional area of the welding, the temperature of the heating plate, and the ambient temperature.
The welding pressure is equivalent to the melting pressure. The function is to forcibly heat the cast iron manhole cover, remove the uneven part of the product surface, and make the cast iron manhole cover face contact with the heating plate, and evenly heat.
Hemming height is used to measure the heating pressure, the time it takes to act on the section of the cast iron manhole cover, that is, the degree of pressure and heating. If you do this, your benefit will be improved.
The temperature of the heating plate refers to the surface temperature of the heating plate, which is generally measured with a surface thermometer. When measuring temperature, consider the influence of ambient temperature. (Except for the equipment that has been considered) The temperature of the hot plate must not only ensure that the product surface melts quickly, but also ensure that the welded product does not degrade due to excessive temperature.
Points of the cast iron manhole cover:
1, strong anti-theft performance: anti-theft alloy cast iron, non-professionals can not destroy, the anti-theft mechanism of the manhole cover fundamentally solves the social problem of manhole cover loss.
2, no noise: all cast iron manhole covers are processed by lathes, which solves the noise caused by wheel rolling.
3, no jump cover: the geometrical design of the cast iron manhole cover and the well circle is reasonable to ensure that the manhole cover will not turn over and shift after the speeding vehicle passes.
4, long life: cast iron manhole cover products can be used normally for more than 30 years under -40oC-80oC open air conditions.
5. Reasonable design: easy installation and opening, convenient for inspection and maintenance of underground pipeline facilities.
6, the cast iron manhole cover is beautiful in appearance: light weight, large load-bearing, clear product casting pattern, excellent anti-slip performance, and pleasing color
7. Good toughness. The impact value is detailed with medium carbon steel, which is more than 10 times that of gray iron.
8. Strong corrosion resistance. In the water spray corrosion test, the corrosion amount in 90 days is only 1/40 of the steel pipe and 1/10 of the gray iron pipe. The service life is twice that of gray iron pipes and 5 times that of ordinary steel pipes.
9. Good plasticity. The elongation rate is ≥7%, which is similar to that of high-carbon steel, while the elongation rate of gray iron materials is zero.
10. High intensity. Tensile strength ób≥420MPa, yield strength ós≥300MPa, which is the same as low-carbon steel and three times that of gray iron materials.
