Analyze the hot rolled aluminum sheet process
The hot rolled aluminum sheet includes the preparation process of rolling raw materials and the rolling process. The preparation process of the raw material for rolling includes sawing of the ingot head and tail, side milling or planing, face milling, etching, welding or bundling of aluminum-clad or composite plates, and heating. The rolling process includes rough rolling and finishing rolling. In the rolling process, it is mainly the process of interaction among the roll, the rolling piece and the emulsion.
Hot rolling refers to rolling performed above the metal recrystallization temperature.
Recrystallization means that when the annealing temperature is high enough and the time is long enough, strain-free new crystal grains (recrystallization core) are generated in the fibrous structure of the deformed metal or alloy, and the new crystal grains continue to grow until the original deformed structure is completely When the metal or alloy disappears, the properties of the metal or alloy also change significantly. This process is called recrystallization. The temperature at which new grains begin to form is called the starting recrystallization temperature, and the temperature at which the microstructure is completely occupied by new grains is called the end Recrystallization temperature, generally what we call the recrystallization temperature is the arithmetic average of the starting recrystallization temperature and the final recrystallization temperature. Generally, the recrystallization temperature is mainly affected by the alloy composition, deformation degree, original grain size, annealing temperature and other factors .
The above is the simple principle of theoretical hot rolling. The main manifestation in the actual production of our aluminum processing industry is that when the ingot is heated to a certain temperature in the heating furnace, that is, the rolling , And the determination of this temperature is mainly based on the phase diagram of the aluminum alloy, that is, in the most ideal case, the heating temperature is determined on the basis of the temperature at 80% of the solidus line of the alloy in the multivariate phase diagram. Involved in the problem of multiple phase diagrams of different alloys, the heating temperature is determined on the basis of 80% of the solidus of the alloy. In the implementation of the system, according to the actual production situation, according to the operation of the equipment, more modifications are obtained. Suitable for the production temperature of the alloy.
Features of hot rolling:
1. Low energy consumption, good plastic processing, low deformation resistance, insignificant work hardening, easy rolling, and reduced energy consumption required for metal deformation.
2. Hot rolling usually uses large ingots and large reduction rolling, with a fast production pace and large output, which creates conditions for large-scale production.
3. The as-cast structure is transformed into a processed structure through hot rolling, and the plasticity of the material is greatly improved through the transformation of the structure.
4. The characteristics of the rolling method determine that there is anisotropy in the properties of the rolled sheet. One is that the material has obvious performance differences in the longitudinal, transverse and height directions, and the second is the deformation texture and recrystallization texture. There is obvious directionality in control performance
Aluminum and aluminum alloy hot-rolled products are generally divided into two categories, one is hot-rolled coils, and the other is hot-rolled thick plates.
Hot-rolled thick plates refer to aluminum and aluminum alloy plates with a thickness of not less than 7.0. The main varieties are hot-rolled plates, annealed plates, quenched or quenched pre-stretched plates, etc. Hot-rolled thick plates are usually produced by block method on hot rolling mills. The traditional process is: ingot homogenization-milling-heating-hot rolling-cut to length-straightening.
Aluminum and aluminum alloy plates and strips with a thickness of less than 7mm are usually produced in hot-rolled coils. The products are mainly used as cold-rolled billets and also used to produce sheets. The modern production process is: ingot milling-heating <integrated heating and heating Chemical>-hot rough rolling-hot continuous milk-bundling and weighing.