The heating rate of aluminum profiles is based on the principle of preventing ingot cracking and excessive deformation.
The holding time should ensure a certain annealing temperature, dissolve the unbalanced phase, and eliminate crystal segregation, but the length of the holding time should be determined according to the alloy characteristics, ingot size, degree of segregation, shape, size and distribution, heating equipment and temperature.
Practice has shown that the speed of the homogenization process gradually decreases over time. Therefore, it is not suitable to prolong the holding time excessively, which will increase the combustion and energy consumption of the metal, and reduce the productivity. After the cooling rate is homogenized, the ingot can be cooled with furnace or air cooling.
The cooling rate of the aluminum profile should not be too fast to avoid the quenching effect. Homogenizing annealing of the ingot can be carried out alone or in combination with heating before hot rolling. The ingot is heated to the uniform annealing temperature, and then reduced to the hot rolling temperature after holding for a period of time, and then hot rolled, which not only reduces the process, but also saves energy consumption.
However, the homogenization annealing temperature is high, the time is long, the energy consumption is large, the composition is simple, the segregation is not serious, the plasticity is good, and no uniform treatment is required.
Generally, super-hard aluminum alloy, hard aluminum, forged aluminum and anti-rust aluminum need to be uniformly annealed.
The influence of extrusion temperature of industrial aluminum profiles on the surface quality: the industrial aluminum profiles extruded in the cold state have accurate dimensions and good surface finish; as the extrusion temperature of industrial aluminum profiles increases, the overall surface finish deteriorates ; As far as the same aluminum profile product is concerned, the temperature of the front section is lower than that of the rear end, and the surface quality of the front end is obviously better than that of the rear end. When the temperature is too high, it is easy to produce pockmarks or pockmarks.