HDPE Steel-Banded Wound Corrugated Drainage Pipe

The steel belt reinforced polyethylene spiral corrugated pipe is a type of pipe that features a winding structure with high-density polyethylene (PE) as the matrix (inner and outer layers) and a surface-coated adhesive resin steel belt composite. **Pipe Applications** It is suitable for various drainage and sewage systems used in municipal, industrial, agricultural, and transportation engineering construction. Utilizing multiple patented technologies from our company in plastic-steel forming and composite technology, the pipe is reliably compounded, enhancing its performance and increasing its ring stiffness. The pipe wall structure consists of three layers: the inner layer is a continuous solid wall PE inner pipe. The outer layer of the inner pipe is reinforced with a ring-shaped corrugated steel belt (formed into a "V" shape with steel plates), and a polyethylene outer layer is compounded over the corrugated steel belt, creating an overall composite spiral corrugated pipe. A typical structure is illustrated in the figure. The elastic modulus of steel is nearly 200 times that of polyethylene, clearly combining the advantages of metal and plastic is an ideal method to achieve high stiffness with low consumption, organically integrating the high stiffness and high strength of steel with the excellent properties of plastic such as corrosion resistance, wear resistance, and flexibility, thereby leveraging the benefits of both while compensating for their shortcomings, realizing a unity of high performance and low cost. **High Ring Stiffness** For ordinary buried drainage plastic wall winding pipes, it is challenging to exceed a large ring stiffness of SN 8, but the new structure of this pipe easily reaches SN 8, SN 12.5, and SN 16, or even higher. On the other hand, this steel-plastic composite pipe, which has a steel pipe as the intermediate layer and polyethylene as the inner and outer layers, also exhibits excellent corrosion resistance. Therefore, this composite anti-corrosion pipe can be applied in various harsh environments. For example, in certain coastal areas, due to the presence of corrosive substances in the soil, using concrete pipes would result in a short service life, raising the expectation for corrosion-resistant plastic buried drainage pipes. However, in the past, the lack of products with high ring stiffness made it impossible to meet design requirements, making metal-reinforced winding structure wall pipes a viable option. **Material Cost Savings** In addition to these performance improvements, another significant advantage is the reduction in material costs. Compared to other plastic pipes of the same diameter and ring stiffness, steel belt reinforced polyethylene (PE) spiral corrugated pipes can save nearly half of the material costs. Polyethylene accounts for only 2/3 of the overall weight of the composite pipe; in the context of rising plastic prices, this presents a very good solution for reducing material costs. The ring stiffness achieved by the thin steel belt pressed into ribs far exceeds the effect produced by a thick polyethylene structural layer. By appropriately designing the thickness and height of the steel ribs, the required ring stiffness can be easily achieved. In metal-reinforced winding structure wall pipes, the function of polyethylene is to resist corrosion and abrasion, so the amount of steel ribs used is minimal, and the amount of polyethylene required is also low. **Combination of Steel and Plastic** The key to the success of metal reinforcement is to ensure a firm bonding between steel and plastic. This requires the steel to be securely bonded to the plastic, with no separation allowed between any two layers. To achieve the desired bonding performance, we conducted extensive research and experiments during the development of the pipes. The process involves pre-coating the steel belt with a special resin as an intermediate layer between the steel and plastic. Additionally, process temperature, pressure, and cooling time must be strictly controlled, ensuring that all layers of steel and plastic are perfectly welded at appropriate temperatures. Another important point in achieving metal reinforcement is to protect the easily corroded metal layer. In the structural design of the pipe, the steel ribs are completely covered by the inner and outer polyethylene. The inner and outer surfaces that come into contact with the conveyed liquid and surrounding soil and groundwater are covered with a certain thickness of polyethylene layer. Therefore, the corrosion resistance and wear resistance of the metal-reinforced winding structure wall pipe are guaranteed.