How is ductile iron manhole cover made?

Ductile iron manhole cover is a kind of ductile iron products, ductile iron through spheroidization and inoculation treatment to obtain spheroidal graphite, effectively improve the mechanical properties of cast iron, especially improve plasticity and toughness, so as to obtain higher strength than carbon steel. Production method and attention: strict requirements for chemical composition, the carbon and silicon content of the raw iron liquid is higher than that of gray cast iron, and the content of manganese, phosphorus and sulfur in ductile iron is reduced; The furnace temperature of molten iron is higher than that of gray cast iron to compensate for the loss of molten iron temperature during spheroidization and inoculation treatment; Spheroidization is carried out, that is, nodularizing agent is added to the molten iron; Inoculant was added for inoculation treatment; Ductile iron has poor fluidity and large shrinkage, so it requires a higher pouring temperature and a larger size of the pouring system. Heat treatment is carried out.

The production method of ductile iron manhole cover: the production of ductile iron manhole cover is first of all strict on the chemical composition, and there are certain requirements for the content of carbon and silicon, and the carbon and silicon content of the original iron liquid is better than that of gray cast iron, and a small amount of elements such as manganese, phosphorus and sulfur should be reduced in ductile iron. The molten iron of ductile iron is at a higher temperature than that of gray cast iron, and it is necessary to add a nodularizing agent when spheroidizing it is carried out, so as to avoid the temperature loss during spheroidization.

Inoculants need to be added during the inoculation process. Ductile iron requires a relatively high temperature in terms of pouring temperature, and the size of the gating system is also relatively large. Because the shrinkage and fluidity of ductile iron flow are relatively large, the principle of sequential solidification is required.

Finally, the mouth and cold iron should be used rationally and heat treated. <>

1) Selection of raw materials: strict requirements for chemical composition, the carbon and silicon content of the raw iron liquid is higher than that of gray cast iron, and the content of manganese, phosphorus and sulfur in ductile iron is reduced (2) Molten iron dissolving: the furnace temperature of molten iron is higher than that of gray cast iron to compensate for the loss of molten iron temperature during nodularization and incubation and disposal (3) Spheroidization of molten iron:

Suspend spheroidization treatment, that is, add nodularizing agent to molten iron (4) inoculation and disposal: participate in the suspension of inoculation and disposal of inoculant (5) molten iron casting: ductile iron has poor activity and large shrinkage, so it requires a higher pouring temperature and a larger size of the gating system, rational use of riser, cold iron, and the use of sequential coagulation criteria (6) prestress elimination:

Thermal treatment is aborted, annealing treatment is discontinued, and nodular iron prestress is removed. (7) Appearance polishing: the appearance of the finished manhole cover is disposed of, and the waste products are returned to the furnace.

8) Anti-corrosion disposal: use asphalt anti-corrosion or electrostatic spraying, stop lead cracking spraying and drying of the finished cast iron manhole cover. (7) Finished products are returned to the warehouse

The finished products are packed and sorted into the finished product warehouse.

Ductile iron manhole cover manufacturers will cast and produce according to different specifications and standards when producing manhole covers, which makes the use of this manhole cover more and more extensive.

1. Ductile iron manhole cover, good raw materials, stable material, high hardness and easy maintenance.

2. High load capacity, able to load 210kn or 360kN, strong impact resistance.

3. Strong anti-theft ability, using double anti-theft design, anti-theft performance is better, and can better maintain the safety of road traffic.

4. The service life is long, and the anti-theft and anti-noise effect of the product is good.

Therefore, in our municipal engineering, the number of ductile iron manhole covers is more.

1. Beijing Xingye Xinxing Pipeline ****Main Products: Cast Iron Pipe Manufacturers, Machine-made Cast Iron Pipes, Ductile Iron Pipes, Flexible Cast Iron Pipes, Cast Iron Drainage Pipes, A-Type Cast Iron Pipes, B-Type Cast Iron Pipes, W-Type Cast Iron Pipes.

2. Jinhong municipal facilities in Sichuan Province.

Main products: Sichuan polymer manhole cover, ductile iron manhole cover, Chengdu stainless steel manhole cover, polymer water grate, ditch cover plate ductile iron water grate, stainless steel water grate factory.

3. Shaanxi Longsheng Jinxin Pipe Industry Co., Ltd. teased this Si Shan Xun.

Main Products: Ductile Iron Water Supply Pipe, Ductile Iron Drainage Pipe, Ductile Fittings, Manhole Cover.

4. Weifang Qiming Machinery ****.

Main Products: Cast Iron Manhole Cover, Ductile Iron Manhole Cover, Cast Iron Grate, Ductile Iron Grate.

5. Feixiang County, Hebei Province, Oriental Casting Lushou ****.

Main products: manhole covers, ductile iron manhole covers, ductile manhole covers, manhole covers for foreign trade exports.

The material is different, the load-bearing is different. There are many more ductile iron manhole covers.

What are the installation specifications of manhole covers?

First, the wellhead, reinforced well ring, and well frame must be consistent.

2. Before installing the manhole cover, the type, size and structure of the manhole cover should be carefully checked to see if it meets the design standards, and check whether there is damage, cracks and other phenomena.

3. The installation of well frames, manhole covers and accessories must be firm, stable and in the correct position. It should be intact and undamaged.

Fourth, commercial concrete must be used; When the concrete curing time is insufficient, early strength and quick-setting concrete should be used; The concrete must be vibrated and compacted and tightly integrated with the road structure.

Fifth, excavation, removal of the wellhead position of the surface layer, base materials shall not disturb the surrounding pavement structure.

6. Before pouring the well ring, the well frame should be stabilized according to the measured elevation; The wellhead inner mold must adopt a stereotyped template.

7. There shall be no less than 6 embedded bolts; If the embedded bolts cannot be installed, the well frame must be reinforced in other ways, such as expansion bolts or reinforcement mesh.

In order to ensure the normal use of cast iron manhole covers, we should pay attention to the quality of installation, so that the size is accurate, the installation is firm, the opening is convenient, and the appearance is clean and beautiful. When laying the well, it must be noted that the inner diameter of the wellhead should be consistent with the inner diameter of the manhole cover grate, and the installed manhole cover should be level with the road surface.

After the concrete or asphalt is poured and laid on the well seat, the cover should be opened and cleaned in time to avoid mortar or asphalt pouring the inspection manhole cover and the seat as a whole, so as not to affect the future opening. When the cement pavement well seat is installed, the brick masonry of the wellhead is smoothed with C25 concrete casting 20cm thick ring beam, and the well seat must be kept square, the whole is flat, and the concrete protection ring with a width of 40cm is cast in the manhole cover (if it is a cement pavement, the concrete protection ring with a width of 20cm can also be cast, and reinforced with steel bars) The maintenance period should be more than 10 days. In order to maintain the beauty of the appearance of the cover, the surface pattern and the clarity of the handwriting, the cover should be covered with a thin iron sheet or the waste engine oil should be brushed on the cover during the construction of the asphalt pavement to prevent the asphalt oil from spraying on the manhole cover; During the construction of cement pavement, the manhole cover should be covered with plastic film to prevent the cement mortar from contaminating the surface of the manhole cover, damaging the surface pattern and handwriting, and the surface of the manhole cover can also be cleaned with water after the construction on the same day.

When installing cast iron manhole cover on asphalt pavement, it is necessary to pay attention to avoid the construction machinery directly rolling the well seat, and when the road surface is cast as a whole, it should be reserved in the road surface slightly larger than the well seat, and placed after the asphalt is paved. (The whole concrete pavement should be installed after the two stones are paved and compacted) to ensure the quality of the manhole cover placement to prolong the service life. Please note that the manhole cover damage caused by improper installation or vehicle overload does not belong to the warranty scope of the factory and does not bear joint and several liability.

The direction of the installation of ductile iron manhole cover is specified.

The advantage of ductile iron manhole cover should be more standardized, and it is more hard and durable.

1.Anti-theft: Put the anti-theft box under the well ring, open the flip cover of the manhole cover, do not use the anti-theft chain, but the anti-theft effect is better, and the rust problem is solved.

2.To prevent falling, there must be a fall arrest grille inside the manhole cover. If the manhole cover is not covered or is missing, injuries caused by people or other objects falling can be avoided.

3.In order to prevent displacement, the well ring is fixed with anchor bolts, and the small round hole in the middle plays a fixed role. After the construction of the manhole cover, the well ring will not cause any mistakes, whether it is rolling or automobile rolling, it meets the construction standards.

4.In order to prevent noise, in order to make the contact surface of the ductile iron dome cover and the well ring more consistent, it should be processed so that there will be no abnormal noise when the car returns through the manhole cover.

5.Non-slip, the surface of the manhole cover should have a diamond pattern to prevent sliding. The connection structure between the rings and the rings must be used. At the same time, the wear resistance coefficient of the ring surface should be increased, the T-shaped protrusion should be increased, and the wear resistance coefficient of the asphalt base material and the ring should be increased.

1.Anti-theft: Set the anti-theft cassette under the well circle, open the folding plate of the manhole cover, do not use the anti-theft chain, but the anti-theft effect is better, and the rust problem is also solved.

2.To prevent falling, there must be a built-in anti-fall grid when checking the manhole cover, if the manhole cover is not covered or lost, to avoid injuries caused by people or other objects falling.

3.To prevent displacement, there are anchor bolts to fix the well ring, and the small round hole in the middle has a fixed effect. After the construction of the manhole cover, the well ring will not cause a wrong mouth, whether it is the rolling of the road roller or the rolling of the car, the construction standard is reached.

4.To prevent noise, the contact surface between the ductile iron dome and the well ring should be machined in order to be more consistent, so that there will be no abnormal noise when a vehicle passes through the manhole cover.

5.Non-slip, the surface of the manhole cover should have a diamond-shaped pattern to prevent slip. The ring must be connected to the ring in the structure mode, and the well ring must be used, and at the same time, the wear coefficient should be increased on the surface of the ring mouth, the T-shaped protrusion should be increased, and the wear coefficient of the asphalt base material and the ring mouth should be increased.