The Wide Uses of Cold-Formed Steel Corrugated Pipes

1. Cold bending forming technology

Cold bending forming technology is a localized and continuous cold processing method, which involves applying external force to the metal at the bending angle through several stages to make it undergo bending deformation, achieving the desired shape.

Compared to hot bending, cold bending offers superior production efficiency, energy consumption and product quality.

As an economical and efficient forming technique, cold bending forming technology is widely used in the manufacture of corrugated steel pipes.

By adjusting the parameters of cold bending forming equipment, the bending radius, angle and length can be controlled to obtain various shapes of corrugated steel pipes.

Cold-formed corrugated steel pipes have the same performance characteristics as hot-formed pipes, such as compressive strength, vibration resistance and malleability, but at a lower cost and with more stable quality, making them highly favored in the construction industry. corrugated steel tubes.

Related Reading: Corrugated Steel Pipe: A Guide to Different Types

2. Advantages of cold bending forming technology

1. Efficiency: Cold bending forming does not require heating of the material, providing faster production speeds, suitable for large-scale manufacturing, with an efficiency up to 10 times greater than that of the stamping process.
2. Lower costs and greater material utilization: For large-scale production, the cost of cold bending is lower than that of stamping, but the mold life is longer. A combined set of rolls can produce different specifications of cold-formed steel, with material savings ranging from 15% to 30% compared to stamping.
3. Energy Conservation and Environmental Protection: Cold bending forming consumes less energy and eliminates the need for significant energy resources, benefiting the environment.
4. Near-net Formation: It allows the online integration of pre-punching, cutting, welding, threading and riveting processes, obtaining an almost final formation of the product. The finished product can be used as a mechanical part without additional processing or with minimal additional work.

3. Applications of cold bending formed corrugated steel pipes in various industries

(1) Sponge City Apps

In sponge city construction:

• Cold-formed corrugated steel pipes can be the main conduits for rainwater collection systems, collecting surface rainwater from urban roofs and roads and directing it to water treatment facilities in the south for processing and utilization (see Figure 5) .
• They can act as components of stormwater infiltration systems, such as infiltration wells or swales, directing stormwater underground, raising groundwater levels and alleviating water shortages (see Figure 6).
• These pipelines can be used in the construction of ecological corridors and green systems, such as ecological conservation areas and wetland parks, offering both ecological restoration and scenic beauty.
• They can serve as integral components of a sponge city's infrastructure, such as squares or sponge roads, improving the city's permeability and reducing the risk of urban flooding.

Compared to cast iron and concrete pipes, corrugated steel pipes formed by cold bending feature lower material costs, high strength, lightweight construction, excellent corrosion resistance, easy installation and a longer service life.

For shorter pipes or scenarios where bending is not necessary, full corrugated steel pipes are more appropriate due to their greater strength and better sealing capabilities.

However, for piping systems that require bending, segmented corrugated steel pipes are more practical as they can be combined to form pipes of different lengths and angles, offering greater flexibility.

For specific situations, such as on-site pipe manufacturing, spiral corrugated steel pipes are best suited as they can be manufactured on-site in various lengths and angles, offering the greatest adaptability.

(2) Application in underground tunnels

In underground tunnel projects (Figure 7), cold-formed corrugated steel pipes are used for drainage systems such as trenches and drainage pipes.

They also serve as ventilation ducts in ventilation systems, ensuring air circulation and the expulsion of harmful gases.

These pipes are used in underground tunnel fire protection systems and are an integral part of cable protection systems, made in various shapes and sizes as cable protection ducts.

Corrugated steel pipes are generally more suitable for small-diameter pipes and short-distance transmission than reinforced concrete main tunnels.

They offer excellent flexibility and sealing, adapting to soil changes and pipe bends. Furthermore, the manufacturing and installation costs of corrugated steel pipes are relatively lower, reducing project costs.

They are also easy to transport, quick to install and have high construction precision.

In culvert projects, cold-formed corrugated steel pipes can be used for drainage, ventilation, support systems (making various shapes and sizes of arches and sidewall structures), and protection systems (protecting culvert structures from water erosion and sediments, as seen in Figure 8).

Corrugated steel pipes used in manholes have excellent vibration resistance and waterproofing ability.

Compared to concrete culverts, corrugated steel pipes have a longer service life (over 100 years), shorter construction cycles, are less challenging to construct, cost less, have high resistance to deformation and low maintenance costs post-completion.

The presence of axial corrugation helps distribute stress and strain along the axial and radial directions, diffusing stress concentrations more effectively.

Especially in cold regions with permafrost, soft soils, expansive soils and loess, the economic benefits are significant. Corrugated steel manholes prevent heating pipes from shifting.

Therefore, removing rust from these heating pipes guarantees the service life of the corrugated manholes. Rust removal methods include technical rust removal, mechanical rust removal and chemical rust removal.

Experience shows that using corrugated steel culverts instead of reinforced concrete for culvert construction brings incomparable advantages in terms of construction cycles, cost, environmental protection and much more.

The use of corrugated metal culverts significantly improves comfort and safety on the roads, preventing the “bouncing car” phenomenon in culverts and combating damage caused by frost in cold regions.

(3) Agriculture Application of Water Conservation

Water conservation agriculture is a crucial component of agricultural production that involves the development, use and management of water resources.

Cold-formed corrugated steel pipes have wide applications in water-conserving agricultural construction, including:

1) Irrigation canals: Corrugated steel pipes act as key components in irrigation canals, diverting water from reservoirs and rivers to farmland to supply crops.

2) Drainage Systems: These pipes serve as primary conduits in agricultural land drainage systems (Figure 9), discharging excess water into rivers and reservoirs, preventing flooding of agricultural land.

3) Reservoirs and storage ponds: Corrugated steel pipes are used in the construction of reservoirs and storage ponds, ensuring a consistent supply of water (Figure 10). Its high resistance and lightness provide greater durability and low maintenance costs.

4) Water-saving irrigation: Corrugated steel pipes are used in drip and sprinkler irrigation, increasing water use and conserving resources.

5) Soil and Water Conservation Projects: These pipes play a role in projects such as anti-slip dams, landfills, preventing soil erosion and protecting the agricultural environment.

6) Aquaculture: Corrugated steel pipes can be used in aquaculture buildings, such as fish ponds and shrimp ponds, providing a consistent water supply and improving the breeding environment.

7) Maintenance of Agricultural Water Facilities: These pipes are essential for the maintenance of agricultural water facilities, such as river dredging and silt cleaning canals, ensuring the normal operation of agricultural water facilities.

8) Water Resources Monitoring and Management: Corrugated steel pipes can be used in the construction of water resources monitoring and management systems such as water level observation stations and water quality monitoring stations, offering accurate data on water resources to guide policy formulation in water conservation agriculture.

In hydraulic and agricultural applications, the type of cold-formed steel corrugated pipe to be selected mainly depends on the following factors:

1. Conditions of use and transported fluid : To transport clean water or fluids with minimal suspended particles, segmented steel corrugated pipes or complete steel corrugated pipes are typically chosen. To transport fluids with a greater quantity of suspended particles, to avoid clogging, corrugated spiral steel tubes must be selected.
2. Pipeline installation conditions : If pipe space is limited and requires many turns, smaller segmented corrugated steel pipes with better maneuverability should be chosen. If the space is ample and the pipe is relatively straight, larger and more economical steel corrugated pipes can be used.
3. Economic considerations : Generally, the cost hierarchy is segmented steel corrugated pipe
4. Technical requirements : Technical complexity and costs are lower for segmented and complete steel corrugated pipes compared to spiral steel corrugated pipes. Consequently, from a technical point of view, segmented and complete corrugated steel pipes are more viable.

(4) Coal mine tunnel applications

In the field of coal mine tunnels, the advantages of corrugated steel pipes lie in their strength, flexibility and corrosion resistance. The environment in coal mine tunnels is harsh and space-limited, requiring high-quality pipeline materials.

Cold-formed corrugated steel tubes perfectly meet these demands. Their strength can be 3 to 5 times greater than that of normal steel pipes, allowing them to withstand high pressures and heavy loads commonly found in coal mine tunnels.

In addition, cold-formed steel corrugated pipes have excellent vibration resistance and anti-corrosion properties, making them suitable for areas with complex geological conditions and frequent natural disasters, ensuring the safe operation of coal mine tunnels.

Furthermore, the installation and maintenance costs of these tubes are lower, effectively reducing the operating costs of coal mine tunnels.

Therefore, cold-formed steel corrugated pipes have vast market potential in coal mine tunnel applications.

For its application in coal mine tunnels, the selection of corrugated steel pipes depends on the following factors:

The media typically transported within coal mine tunnels are compressed air and water, with few suspended solid particles present. Additionally, coal mine tunnel spaces are narrow, with many bends in the ducts.

Therefore, segmented steel corrugated pipes, due to their smaller size and better maneuverability, are more suitable for installation in tight spaces with many curves.

Full steel corrugated pipes and spiral steel corrugated pipes are less appropriate in these situations.

In conclusion, for coal mine tunnel applications, segmented steel corrugated pipes are the preferred choice.

(5) Applications in bridge and tunnel construction

In bridge and tunnel projects, cold-formed corrugated steel tubes feature high strength and durability.

In bridge projects, cold-formed steel corrugated tubes are commonly used for bearing structures of bridge piers and piers, as shown in Figures 11 and 12.

Given the vast span and heavy loads of highway bridges, there is a great demand for structural piping material strength. The strength of cold-formed corrugated steel pipes can be 3-5 times that of ordinary steel pipes, fully meeting the requirements of bridge structures.

Furthermore, corrugated steel pipes have inherent ductility, allowing them to absorb impacts from dynamic loads, thus increasing structural safety.

In tunnel projects, cold-formed steel corrugated tubes are often used in supporting structures such as arch constructions and anchor bolts. Tunnel environments are harsh, requiring high strength and durability from the materials used.

Cold-formed corrugated steel tubes not only have high strength, but, through surface treatments, they offer excellent corrosion resistance, ensuring long-term structural safety.

Furthermore, due to their lightness, they are easy to transport and install, especially in confined spaces such as tunnels.

(6) Applications in highway construction

Today, with accelerated highway construction around the world, tens of thousands of kilometers of highways require large quantities of structurally safe materials. This demand paved the way for the application of cold-formed corrugated steel tubes.

The selection of cold-formed steel corrugated pipes in highway applications is mainly based on the following considerations:

• For larger load-bearing requirements, it is advisable to choose full steel corrugated pipes or spiral steel corrugated pipes. These types have thicker walls, providing superior resistance to axial and radial pressures.
• For lower load needs, segmented corrugated steel pipes may be sufficient and are more economical.
• For larger diameters, due to manufacturing constraints, full-length and spiral corrugated steel pipes have certain limitations. In these cases, segmented corrugated steel pipes are the only option. If the diameter is within a specific range, any type of steel corrugated pipe can meet the requirement.

In summary, the selection of corrugated steel pipes for highway applications requires comprehensive judgment based on the specifics of the project.

Generally speaking, for smaller diameters and lower load requirements, segmented steel corrugated pipes are ideal. For larger diameters or greater load-bearing demands, full-length or spiral corrugated steel pipes are more suitable.

4. Existing Challenges

Although cold forming technology is widely used in the corrugated steel pipe industry, it still faces certain challenges and difficulties.

1. Product geometry is difficult to control. Cold forming is a continuous processing technique and the deformations that occur during the process are difficult to control and predict accurately. This makes it difficult to strictly control the geometric dimensions and shape of the product, limiting its application in areas that require high precision and strict tolerances.
2. There is room to increase production efficiency. Current cold forming equipment and techniques have not yet realized efficient and fully automated large-scale production. Both production efficiency and technological levels can still be improved.