Ductile Cast Iron Round Manhole Cover With Snap Ring

I. Technical Features

1.Material & Process

 -Ductile Iron Base Material:  

•   -Magnesium/rare earth element nodularization treatment ensures spherical graphite distribution. Tensile strength ≥420 MPa, elongation ≥10%, impact toughness (≥12 J/cm²) far exceeds gray iron (HT250), combining cast iron's wear resistance with steel's toughness.  
•   -Density 7.3 g/cm³, no scrap melt value, reducing theft motivation at the source.  

 -Anti-corrosion Process:  

•   -Surface zinc spraying (zinc layer ≥80μm) + asphalt coating or epoxy resin spraying. Salt spray corrosion resistance ≥1000 hours (ASTM B117), suitable for soil and humid environments with pH 5-10.  

2.Spring-Lock Security Structure  

•  -Dual Spring Locking: Built-in high-strength springs (65Mn steel), requires specialized tools (e.g., T-wrench) for opening. Tampering time ≥20 minutes, reducing theft incidents by over 90%.  
•  -Multi-point Fixation Design: 3-4 lock points distribute pressure evenly, preventing single-point failure and cover shifting or bouncing.  

3.Functional Optimized Design  

•  -Anti-slip Surface: Diamond knurling or fish-scale pattern treatment, friction coefficient ≥0.65, excellent slip resistance in rain/snow.  
•  -Noise Reduction & Sealing: Rubber gasket embedded in cover-frame joint reduces vehicle noise by 10-15 dB and prevents sewage leakage.  
•  -Load Reinforcement: Bottom reinforcing rib structure, load classes from C250 (25 tons) to E600 (60 tons), adaptable to various load scenarios.  

II. Core Advantages  

1.Ultimate Security & Safety  

•  -Spring-lock mechanism + non-recyclable material provides dual security, reducing theft/damage by 95% compared to traditional covers.  
•  -Grate gap ≤15mm (EN 124 standard), preventing small object drops and ensuring pedestrian safety.  

2.Ultra-high Strength & Anti-settlement Capability  

•  -Compressive strength 400-600 MPa, passes EN 124 D400 test (40-ton fire truck repeated rolling without deformation).  
•  -Flexible connection design (rubber buffer layer) allows ±3mm foundation settlement, preventing misalignment or breakage.  

3.Long Lifespan & Low Maintenance  

•  -Anti-corrosion coating + ductile iron base material, service life ≥30 years (2-3 times that of composites).
•  -No repainting maintenance; daily cleaning requires only high-pressure water washing. Whole-life cost 40% lower than gray iron.  

4.Environmental Adaptability  

•  -Temperature resistance range -40℃ to 350℃, resistant to freeze-thaw cycles, suitable for extreme cold (e.g., Northeast China) or hot/rainy regions (e.g., South China).  
•  -Epoxy coating upgrade resistant to strong acids/alkalis (pH 3-12), suitable for chemical plants or coastal salt spray environments.  

III. Application Scenarios & Load Matching  

1.High-Security Zones:  

•  -Highways, airport runways: Anti-theft design + D400 load class prevents traffic accidents caused by stolen covers.  
•  -Military bases, nuclear plants: Spring-lock + non-recyclable material secures underground utilities of sensitive facilities.  

2.Urban Core Functional Areas:  

•  -Subway stations, commercial districts: Noise reduction/sealing minimizes public disturbance; flexible connection adapts to underground construction settlement.  
•  -Hospitals, schools: Anti-drop gap + high-friction pattern reduces pedestrian slip risks.  

3.Special Environments:  

•  -Coastal areas (e.g., Xiamen Island Ring Road): Epoxy coal-tar coating resists chloride ion erosion.  
•  -Chemical parks: PTFE anti-corrosion coating resistant to strong acid/alkali splashes (pH 1-14).  

IV. Technical Standards & Certifications  

-International Standards:  

•  -EN 124 D400 (Load-bearing)  
•  -ISO 15874 (Sealing systems)  

-Chinese Standards:  

•  -GB/T 23858-2009 "Manhole Covers"  
•  -CJ/T 512-2017 "Spring-Lock Anti-theft Manhole Covers"  

-Special Certifications:  

•  -Ministry of Public Security Security & Protection Product Certification (GA Certification)  
•  -Explosion-proof Certification: Ex db IIC T6 Gb (Chemical Industry Version)  

Conclusion  

The Ductile Iron Spring-Lock Manhole Cover redefines protection standards for high-value infrastructure through Anti-theft Revolution, 10-Second Quick Access, and Smart Pre-embedding:  

• 1.Crushing Theft Resistance: 50 kN anti-break-in force + 100,000 key combinations, making theft attempts futile and unprofitable.  
• 2.Maintenance Revolution: 5-second opening + 10-year maintenance-free, reducing municipal emergency response costs by 60%.  
• 3.Risk Foresight: Methane/tilt monitoring prevents explosions and settlement accidents at the source.  

This product is an essential configuration for urban lifeline infrastructure (power/gas/telecom) and the cornerstone of smart city safety!