Preparation method for preparing 2-series aluminum alloy annealed fine-grain thin plate

The invention provides a preparation method for preparing a 2-series aluminum alloy annealed fine-grain thin plate. The preparation method comprises the following steps that homogenization process treatment is carried out on an aluminum alloy cast ingot to obtain a high-quality soaking cast ingot with the grain size of 100-150 um; hot rolling treatment is carried out on a composite cast ingot plate to obtain a hot-rolled composite cast ingot plate; cold rolling treatment is carried out on the hot-rolled composite cast ingot plate to obtain a cold-rolled composite cast ingot plate; annealing treatment is carried out on the cold-rolled composite cast ingot plate to obtain an aluminum thin plate primary product; and the aluminum thin plate is subjected to solid solution aging treatment to obtain an aluminum thin plate finished product. According to the preparation method, the GBT 3246.1-2012 standard grain size grades are all up to grade 1, and the 2-series aluminum alloy annealed fine-grain thin plate has the v