Causes and solutions of false joints in aluminum alloy profiles

In the process of aluminum production, it often encounters problems such as surface false joints, surface scratches, mechanical lines, surface black lines, surface feel unevenness, serious welds, etc. The low welding force is due to the low extrusion force, which causes the low extrusion force of aluminum alloy profiles to be caused by both mold factors and process. Extrusion temperature and extrusion speed of aluminum alloy profiles The high temperature of aluminum rods is conducive to the diffusion and bonding of metals, but it also leads to the intensification of the phenomenon of metal bonding molds, and at the same time, the high temperature leads to the acceleration of the growth and growth rate of metal structure, so that the weld structure will be thicker. If the extrusion speed is too high, the metal deformation work will increase, and the metal temperature will increase greatly. In addition, if the extrusion temperature is too high, the extrusion force will be reduced, which will reduce the welding force. In fact, when graphite products are used as the discharge material, the side in contact with graphite is also prone to black bands after oxidation.

The failure of aluminum alloy profile hot extrusion dies is mainly caused by cracking, wear, scouring corrosion, overheating and thermal fatigue cracks. The lubrication conditions of the mold have a great impact on the life of the mold. In the extrusion process of aluminum and aluminum alloys, it is also necessary to use lubricants to reduce the friction between the metal and the extrusion cylinder wall, perforated needle and mold surface, and reduce the adhesion between them and the wear of the tool.

In the past, due to the limitations of technical factors such as the research and development of new materials, improper use of lubricants often led to surface pollution of products, and lubricants may flow into the center of the product, forming a more obvious "extrusion tail". Therefore, "lubrication-free extrusion" has been used for many years in the extrusion of aluminum and aluminum alloy rods and profiles. In the extrusion of pipes and hollow aluminum alloy profiles, it is only lubricated on the surface of the die and the perforated needle. In recent years, in order to extrude large and complex duralumin alloy profiles on extrusion machines with limited extrusion force, and at the same time, in order to improve the extrusion speed and obtain extrusion materials with more uniform microstructure, the lubrication extrusion method has been extensively studied.

Especially for the aluminum profile in the process of high-temperature extrusion, welding quality problems, mold working belt will appear scratches and other problems, spraying high-temperature lubricant, in the normal temperature state can prevent rust on the surface of the working belt, long-term warm-up period can protect the surface of the working belt from decarburization and oxidation, maintain the original hardness of the surface of the working belt, do not produce soft spots and soft belts, aluminum alloy profiles can increase the lubrication between the mold and the mold, reduce the friction with the mold, avoid mold blocking and collapse, make product production smoother, reduce the welding quality problem, Reduce the generation of ripples, improve the smoothness of the product, prevent bonding, avoid sticking molds, stick aluminum, reduce the number of repairs of molds, and extend the use time of molds.