Aluminum tube butt welding aluminum plastic tube
Another important aluminum-plastic composite pipe is the butt-welded aluminum tube. Its aluminum tube layers are connected using a butt-welding process, where the two edges of the aluminum strip are directly butted and then welded to form a tubular structure with no overlap, which is then composited with the inner and outer plastic layers. This structural design makes the cross-section of the aluminum tube layer more uniform, eliminating thickness differences at the overlapped areas. This allows for more balanced force when subjected to internal pressure, effectively reducing stress concentration and improving the pipe’s pressure resistance and fatigue resistance. Compared to lap-welded pipes, butt-welded aluminum tubes have smoother inner walls and less fluid resistance, which helps improve transportation efficiency. At the same time, the aluminum tube layer has greater overall rigidity and better dimensional stability in high-temperature environments, making it suitable for scenarios requiring higher pipe performance.
The production process for butt-welded aluminum-plastic pipe differs significantly from lap-welded pipe in the forming and welding stages, resulting in a higher level of technical complexity. First, the aluminum strip undergoes pretreatment before entering the forming unit, where it is rolled into a tube using precision dies. The two edges are precisely butted together, and the butt gap must be kept to a very small range, typically no more than 0.1mm, to ensure weld quality. The welding process utilizes either laser or plasma welding. Laser welding utilizes a high-energy-density laser beam to instantly melt and fuse the butt edges, creating a high-quality weld. Laser welding utilizes the high temperatures generated by a plasma arc and is suitable for joining thicker aluminum strips. During the welding process, a sophisticated control system ensures accurate butt edge alignment and consistent welding parameters to avoid defects such as misalignment and incomplete penetration. After welding, the aluminum tube undergoes rigorous nondestructive testing to ensure acceptable weld quality before entering the lamination process, where it is combined with the inner and outer plastic layers and adhesive layer. Finally, it undergoes cut-to-length and performance testing to qualify as a qualified product.
Butt-welded aluminum-plastic pipes (APCs) excel in hot water supply and heating systems, and are particularly suitable for transporting high-temperature fluids. In hot water piping systems for homes and commercial buildings, the aluminum tube layer utilizes a butt-welded structure, allowing it to withstand long-term temperatures exceeding 80°C without deformation. The plastic layer, made of high-temperature-resistant PPR or PE-RT materials, bonds tightly to the aluminum tube layer, preventing delamination when exposed to temperature fluctuations. The pipes also offer excellent compressive strength, with an operating pressure exceeding 1.6 MPa, meeting the pressure requirements for hot water transportation in high-rise buildings. In central heating systems, APCs can be used to connect radiators and main pipes. Their smooth inner wall reduces energy loss during hot water transportation, while the barrier effect of the aluminum tube layer prevents oxygen from entering the system, reducing corrosion on pipes and radiators and extending the life of the heating system.
In the field of industrial fluid transportation and special pipelines, aluminum tube butt-welded aluminum-plastic pipes also have unique application advantages. In the food processing industry, they can be used to transport fluids that are easily contaminated, such as juice and dairy products. The smooth inner wall does not easily breed bacteria. The aluminum tube layer blocks oxygen to maintain the freshness of the fluid. The pipe material meets food hygiene standards and will not cause contamination to the fluid. In the chemical industry, for the transportation of some liquids that are not highly corrosive, such as dilute acid and alkali solutions, the corrosion resistance and sealing properties of butt-welded aluminum-plastic pipes can ensure the safety of the transportation process and avoid environmental pollution caused by leakage. In addition, in the pipeline systems of ships and vehicles, this type of pipe has obvious advantages in lightweight and vibration resistance, which can reduce the weight of the equipment and noise during operation, while resisting fatigue damage caused by vibration.
With advances in industrial technology, the performance of aluminum-plastic butt-welded pipes continues to improve, and their applications continue to expand. Manufacturers are developing new welding technologies, such as fiber laser welding, to further enhance weld strength and sealing. They are also optimizing composite processes and employing co-extrusion technology to strengthen the bond between layers. To meet environmental requirements, some products utilize recyclable materials and lead-free adhesive layers to minimize environmental impact. In the future, with the development of high-end manufacturing and clean energy industries, demand for high-performance composite pipes will continue to increase. With its excellent overall performance, aluminum-plastic butt-welded pipes are expected to find application in more high-end applications, with promising market prospects.
