With the rapid development of the aviation industry, higher and higher requirements are placed on aluminum alloy semi-finished products, especially for high-speed military and civil aircraft, the most complete semi-finished products are required to make the structure of each component more reasonable and ensure the highest structural quality. Lightweight, maximum strength and rigidity, while greatly reducing the number of parts, reducing assembly, joining and maintenance costs, ensuring a perfect and beautiful surface (good sealing, no seams, no deformation, etc.). As a result, aluminum profiles
have become an important object for the development of all countries in the world. At present, large, complex and integral special aluminum alloy extruded profiles have become an indispensable and important structural material in the aviation industry.
1. Aluminum alloy profiles are particularly important structural parts on aircraft, and the profiles are required to have excellent mechanical properties. Therefore, the profiles must be extruded with duralumin or super-hard aluminum alloy.
2. The shape is complex, the outline size and the cross-sectional area are large. For example, the diameter of the circumscribed circle can reach 100~800mm and the length can reach 18m. Therefore, extrusion forming is very difficult, not only requiring a heavy extruder of more than 500 tons and a large diameter and high specific pressure extrusion cylinder, but also designing and manufacturing large molds, which are all highly difficult technologies.
3. Since aluminum profiles are used as structural parts of key parts of aircraft, they are required to have good comprehensive properties and uniform structure, especially for coarse-grained rings, and the coarse-grained ring defects in quenched products after extrusion it's hard to avoid.
4. For aluminum profiles such as cross-shaped girders and comb-shaped joint plates, on the one hand, their cross-sectional area is large, which often makes the extrusion deformation coefficient relatively small, and on the other hand, they must bear a large load in the lateral and height directions. Therefore, it is required to have high mechanical properties in the lateral and vertical directions. This contradiction is often an important reason for the scrapping of profiles.