Views:1 Author:Site Editor Publish Time: 2021-09-30 Origin:Site
In order to obtain higher mechanical properties, a higher extrusion temperature should be selected. However, for 6063 alloy, when the extrusion temperature is higher than 540℃, the mechanical properties of the profile will no longer increase. When it is lower than 480℃, the tensile strength may be unqualified.
Excessively high extrusion temperature will cause bubbles, cracks and serious scratches on the product surface caused by aluminum sticking to the mold, and even burrs and other defects. Therefore, in order to obtain products with high surface quality, lower extrusion temperatures are often used.
In order to improve the efficiency of aluminum extrusion production, good equipment is also the key, especially the three major parts of aluminum extrusion press, aluminum rod heating furnace, and mold heating furnace. The most important thing is to have a good extrusion workshop. And extrusion workers.
Aluminum bars and aluminum rods need to be pre-heated before extrusion to reach the solvus temperature (Solvus temperature), so that the magnesium in the aluminum rods can melt and flow evenly in the aluminum material. When the aluminum rod is put into the extruder, the temperature does not change much.
When the extruder starts, the huge pushing force of the extrusion rod extrudes the softened aluminum material from the die hole, resulting in a great friction force, which is converted into temperature, and the temperature of the extruded profile exceeds the melting point. Line temperature, at this time, magnesium melts and flows around, which is extremely unstable.
The temperature increase must not be higher than the solidus temperature, otherwise the aluminum will melt, and the profile cannot be formed. Aluminum rod temperature The temperature of the aluminum rod should be kept between 400-540°C (take 6xxx series aluminum alloy as an example), preferably 470-500°C. Too high will cause tearing, and too low will reduce the extrusion speed (because the aluminum material must be softened) most of the friction force of extrusion will be converted into heat, leading to temperature rise, which is related to extrusion speed and extrusion pressure.
This is the three temperatures that everyone often talks about: aluminum rod temperature, mold temperature, extrusion barrel temperature, and the other is that the extrusion speed must be controlled well.
Outlet temperature The outlet temperature should be kept between 550-575°C, at least above 500-530°C, otherwise the magnesium in the aluminum alloy will not melt and affect the metal performance. However, it must not be higher than the solid-melt phase line. Too high outlet temperature will cause tearing and affect the surface quality of the profile.
The best extrusion temperature The temperature of the aluminum rod should be adjusted in conjunction with the extrusion speed, so that the extrusion temperature difference is not lower than the Solvus temperature and not higher than the Solidus temperature, which is 620°C. Different alloys have different melting temperature. For example, the melting temperature of 6063 alloy is 498°C, while the melting temperature of 6005 alloy is 510°C.