LuZhongBao 36-inch (≈914 mm) ductile iron round manhole cover is a high-performance protective product designed for ultra-heavy-duty scenarios such as urban arterial roads, port terminals, and airport runways. Strictly compliant with GB/T 23858 national standards and EN124 European standards, it is precision-cast from QT500-7 high-strength ductile iron. Its large 36-inch diameter perfectly adapts to large inspection manholes, capable of withstanding extreme loads and frequent traffic flow. The cover features an internal radial reinforcement rib structure combined with a thickened design (typically ≥60 mm), evenly distributing loads to the frame and road base, effectively preventing deformation or fracture caused by stress concentration.
The surface is treated with hot-dip galvanizing or epoxy asphalt coating, with salt spray resistance exceeding 3,000 hours, ensuring long-term stable performance in corrosive environments. With precision casting and strict quality control, LuZhongBao makes this cover a reliable choice for national infrastructure projects, providing solid protection for urban operational safety.
