1. The Best 3003 aluminum plate is an aluminum-manganese alloy. As shown in the Al-Mn system binary phase diagram, although the solubility of Mn in Al changes greatly, it has no obvious strengthening effect, so it cannot be strengthened by heat treatment, so the strength is higher than that of pure Al. high. Mn is very prone to intragranular segregation during ingot casting, and the microdomain distribution of Mn is uneven, and Mn can significantly increase the recrystallization temperature. Therefore, the low Mn part has been recrystallized during annealing, and the grains begin to grow, while the high Mn part is recrystallized. It has not been recrystallized, resulting in extremely coarse grains of the annealed sheet. The way to prevent it is to relax the limit of impurity Fe (0.5%~0.65%) and reduce the segregation of Mn, so as to facilitate the acquisition of fine-grained sheets. However, when the content of Mn and Fe reaches the allowable upper limit at the same time, coarse primary compounds will appear, which is unfavorable for rolling, so the actual amount of Mn added should be controlled below 1.45%. Homogenizing the ingot to eliminate the intragranular segregation of Mn can prevent the annealed material from forming a coarse grain structure; rapid annealing of the sheet, such as annealing in a salt bath or air cushion furnace or induction annealing can prevent coarse grains The formation of Si can form Al(Fen)si compound, which destroys the grain refining effect of Fe. It is a harmful impurity and should be limited to less than 0.3%. With the restriction added, the effect of Zn is not significant.

2. The 3004 aluminum plate has more magnesium than the Best 3003 aluminum plate. The effect of Mg has two sides. In addition to damaging the surface quality, it also has a solid solution strengthening effect, which can increase the strength of the Al-Mg alloy by 10%. Therefore, the Al-Mg-Mn system Alloys such as 3004 type alloys are widely used. Al-Mn alloy has higher strength than pure Al, high plasticity, corrosion resistance (close to pure aluminum) and excellent weldability, mostly in annealed, semi-hard, hard and extra-hard (H19) states use. And because Al-Mn alloy has good pressure processing performance, it can be processed into various semi-finished products, and it is widely used in various sectors of the national economy. It has become the aluminum strip alloy with the largest output in the world.