The heating speed of aluminum profiles is based on the principle that the ingot does not cause cracking and excessive deformation. Holding time The holding time should ensure a certain annealing temperature to dissolve the non-equilibrium phase and eliminate intra-grain segregation, but it should be based on alloy characteristics, ingot size, degree of segregation, shape and size and distribution of the second phase, heating equipment and temperature , Determine the length of the holding time. Practice has proved that the rate of the homogenization process increases with time, but gradually decreases from large. Therefore, it is not appropriate to extend the holding time excessively, which will increase the burning and energy consumption of the metal and reduce the productivity. After the cooling rate is equalized, the ingot can be cooled with the furnace, or it can be air-cooled.
The cooling speed of aluminum profiles should not be too fast for hard aluminum, etc., so as not to cause the quenching effect. The ingot homogenization annealing may be performed alone or in combination with heating before hot rolling. That is, the ingot is heated to the homogenizing annealing temperature, and after being held for a certain period of time, it is reduced to the hot rolling temperature, followed by hot rolling, which reduces the process and saves energy consumption. However, the homogenization annealing temperature is high, the time is long and the energy consumption is large. For alloys with simple composition, less severe segregation and good plasticity, it is not necessary to perform homogenization treatment.
Generally, super-hard aluminum alloys, hard aluminums, wrought aluminums, and rust-proof aluminums need to be uniformly annealed.