Cast iron manhole cover

Cast iron manhole covers are divided into nodular cast iron manhole covers and gray cast iron manhole covers. Generally speaking, the same weight nodular cast iron manhole covers are more resistant to compression than gray iron manhole covers. The material of gray iron manhole cover is generally HT200, and the material of nodular manhole cover is generally QT500-7.


Ductile iron manhole covers are mainly made of nodular cast iron, and the quality of such manhole covers involves the problem of nodularization. The common coating for castings is anti-rust asphalt paint. Of course, the surface of ductile iron manhole cover is also treated with anti-rust asphalt paint. Ductile iron manhole covers have the advantage that due to their high strength and good toughness, the ductile iron manhole covers are about 30% lighter than the same type of gray cast iron manhole covers.


Good toughness. The impact value is similar to medium carbon steel, which is more than 10 times that of gray iron material.

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 pipe and 5 times that of ordinary steel pipe.

Good plasticity. The elongation is ≥7%, which is similar to that of high carbon steel, and the elongation of gray iron material is zero.

high strength. Tensile strength ób ≥ 420 MPa, yield strength ós ≥ 300 MPa, the same as low carbon steel, three times that of gray iron material.

Due to the nodular graphite microstructure of spheroidal graphite cast iron, spheroidal graphite cast iron is superior to cast steel in terms of weakening the vibration ability, so it is more conducive to reducing stress. An important reason for choosing spheroidal graphite cast iron is that spheroidal graphite cast iron has a lower cost than cast steel. The low cost of ductile iron makes this material more popular, the casting efficiency is higher, and the machining cost of ductile iron is less.

The strength of nodular cast iron is comparable to the strength of cast steel. Ductile iron has a higher yield strength, the lowest yield strength is 40k, while the yield strength of cast steel is only 36k. In most municipal applications, such as: water, salt water, steam, etc., the corrosion resistance and oxidation resistance of nodular cast iron exceed that of cast steel.

Application areas:

Municipal parks, highways, communications, electricity, water, communities, schools and other parks.

Resin manhole cover

The resin manhole cover has the advantages of light weight, high strength, excellent fatigue resistance, breakage safety, simple molding, low noise of car milling, good chemical resistance, good acid and alkali resistance and beautiful appearance. Its comprehensive performance and economic indicators have surpassed the cast iron manhole cover, and can also solve the problem of the stolen cast iron manhole cover. At the same time, it can reduce the consumption of resources and has important economic and social values.


  1. Strong anti-theft performance: The resin composite manhole cover is made of unsaturated resin, glass fiber and other materials and the steel bar skeleton is compounded by a special production process. It is formed by high temperature grinding and pressing once, the material has no recycling value, and it is very difficult to take out the steel bar (take out the steel bar The cost exceeds the value of the reinforcement) and therefore has the function of active anti-theft.
  2. Large bearing capacity: the bottom adopts a special pot bottom structure, which increases the force area by more than ten times or even dozens of times. The continuous reinforcing fiber yarn used guarantees the integration of the fiber yarn and the glass fiber cloth from the material, so that the product has sufficient bearing capacity. And meet or exceed national standards.
  3. Long service life: through the use of high-performance resin, glass fiber and special production process formula, it ensures the penetration of the resin in the glass fiber, greatly enhances the adhesion of the two, so that the material is not affected by the cyclic load Internal damage is produced, thus ensuring the service life of the product and the same superiority of other resin composite manhole covers. Eliminate the disadvantages of poor adhesion.
  4. Beautiful and practical, high grade: According to the needs of high-end customers, we can make a personalized design of complex LOGO and multiple colors on the surface of the same manhole cover, so that the patterns are delicate, the colors are bright and distinct. And can be made according to customer needs a variety of stone surface and the same color imitation stone surface and color.
  5. High temperature/low temperature resistance, good insulation performance and strong corrosion resistance: the product is corrosion-resistant, non-toxic and harmless. No metal additives, it has a real insulation effect. It can be used in complex, changeable, harsh and demanding places. The product has been tested by relevant national authoritative testing institutions and has obvious acid and alkali resistance, corrosion resistance, anti-aging and other indicators that have reached and exceeded national standards.
  6. Environmental protection, non-slip, low noise: The product does not slip after the car is crushed, there is no harsh noise and reverse phenomenon. At the same time, due to the light weight of the product and the precise closure of the cover and the seat, it overcomes the problems of “jumping, rocking, ringing, displacement” of other inspection manhole covers.


Product Features:

The biggest feature of the resin composite manhole cover is made of polymer composite materials, without any recycling value. After the promotion and use of resin manhole covers, the problem of stealing manhole covers and causing urban black holes will be solved. The difference from the manhole cover on the market is that it is pressed out by a hydraulic machine and has a high impact strength. ”

This resin composite manhole cover is made of glass fiber and resin as basic materials, and curing agent, accelerator and other auxiliary materials. Its weight is two-thirds lighter than cast iron manhole covers, and its service life is more than 20 years, which is twice that of cast iron manhole covers, and the price is only 80% of the cast iron manhole covers. At the same time, this manhole cover also has the characteristics of insulation and no noise. Chifeng City Product Quality Supervision and Inspection Institute carried out load and impact strength tests on this manhole cover, and found that the load force of this manhole cover was 24 tons, and the impact strength also exceeded the ordinary manhole cover.


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Eternal Bliss Alloy Casting & Forging Co, Ltd.

Technical Dept.


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