(1) Heating method of aluminum alloy cast rod
The aluminum alloy casting rod is heated by power frequency induction heating. The characteristics of this heating method are:
a. The heating time is short, and it can reach about 500 ℃ within 3 minutes;
b. The extrusion temperature is controlled accurately, and the error does not exceed ±3°C.
If the resistance furnace is used for slow heating, the Mg2Si phase will be precipitated, which will affect the strengthening effect.
(2) Extrusion of aluminum profiles
The following factors have been changed, and the extrusion process of 6082 alloy aluminum profiles has been rationally formulated.
1. The deformation resistance of 🔗6082 lega is large, so the temperature of the cast rod should be on the upper limit (480-500℃);
2. The temperature of aluminum extrusion die should also be high;
3. In order to prevent tail shrinkage or the involvement of air bubbles, oxide skin, and impurities, the excess pressure should be left longer;
4. In order to make the main strengthening phase of the alloy Mg2Si completely solid solution, it is necessary to ensure that the quenching temperature is above 500 °C, and the extrusion outlet temperature of this profile should be controlled at 500-530 °C;
5. 6082 aluminum alloy has high quenching sensitivity. The alloy contains Mn, which promotes the formation of intragranular intermetallic compounds and adversely affects the quenching performance. The quenching cooling strength is required to be high and the cooling speed is fast, and the temperature must be rapidly reduced to below 50 °C by water quenching;
6. After the 6082 aluminum alloy profile is sawed, the frame should be protected at a certain interval, and it should not be discharged too densely.