Aluminum alloy tube is widely used in many fields due to its advantages such as light weight, high strength and good corrosion resistance. However, during the bending process, defects such as wrinkling and cracking are prone to occur, which affect the product quality and performance. Therefore, it is crucial to understand and master the methods to avoid these defects.
The mechanical properties and processing properties of aluminum alloy tubes of different models and states are different. For example, 6061 aluminum alloy has good machinability and corrosion resistance and is suitable for general bending processing. When selecting tubes, the appropriate alloy model and heat treatment state should be selected according to the specific bending requirements. For the case of a small bending radius, an aluminum alloy tube with higher strength and better toughness should be selected to reduce the risk of rupture. At the same time, the quality of the tube should be ensured, and tubes with internal defects or surface damage should be avoided, because these places are prone to cracks and expansion during the bending process, eventually leading to rupture.
Accurate calculation of parameters such as bending radius, bending angle and tube elongation is the key to avoiding defects. If the bending radius is too small, the outer side of the tube will be subjected to excessive tensile stress, which may easily lead to rupture; if the bending radius is too large, the inner side of the tube may be subjected to excessive compressive stress, causing wrinkles. According to the diameter, wall thickness and material properties of the tube, the appropriate bending radius can be accurately calculated through formulas or empirical charts. At the same time, the bending angle should be accurately controlled to avoid excessive bending. In addition, considering the elongation of the tube during the bending process, a reasonable processing allowance should be reserved to prevent rupture due to insufficient length or wrinkles due to excessive length.
Common aluminum alloy tube bending processes include bending around, pushing and pulling. Bending around is suitable for bending small diameter tubes, which can better control the bending radius and shape, but wrinkles may occur for large diameter tubes. Push bending is suitable for bending large diameter tubes, which can effectively avoid wrinkles, but requires a large thrust and has high requirements for the ends of the tube. The stretch bending process combines the advantages of bypass bending and push bending. By applying appropriate tension during the bending process, it can not only reduce the compressive stress on the inside of the pipe and prevent wrinkling, but also increase the tensile strength on the outside of the pipe and reduce the possibility of rupture. According to the specifications and bending requirements of the pipe, select the appropriate bending process and optimize the process parameters, such as bending speed, feed rate, etc.
High-quality molds and equipment are important conditions for ensuring bending quality. The shape, size and surface quality of the mold should match the specifications and bending requirements of the pipe. The fillet radius of the mold should be appropriate. Too small will cause scratches and cracks on the surface of the pipe, and too large may cause wrinkling. The surface of the mold should be smooth to reduce friction and avoid damage to the surface of the pipe. At the same time, the mold should be inspected and maintained regularly, and the worn mold should be repaired or replaced in time. In terms of equipment, it is necessary to select bending equipment with high precision and good stability, and ensure that the various parameters of the equipment can be accurately controlled and adjusted.
Before formal bending, pre-bending the pipe can improve the stress distribution of the pipe and reduce rebound and wrinkling during the bending process. The angle and radius of the pre-bending should be reasonably designed according to the characteristics of the tube and the final bending requirements. After the bending is completed, the tube is properly post-processed, such as straightening, stress relief annealing, etc. Straightening can correct the deformation of the tube during the bending process to ensure its straightness and dimensional accuracy. Stress relief annealing can eliminate the residual stress inside the tube, improve the strength and toughness of the tube, and prevent cracks or deformation during subsequent use.
In the bending process of aluminum alloy tube, defects such as wrinkling and rupture can be avoided by a variety of methods. From the selection of tubes, the calculation of bending parameters, to the selection of bending processes, the use of molds and equipment, as well as pre-bending and post-processing, strict control and careful operation are required. Only when each link cooperates with each other and optimizes synergistically can the quality of aluminum alloy tube bending be effectively improved, the generation of defects can be reduced, and the high quality requirements of aluminum alloy tube bending parts in different fields can be met.
