Study Of Microstructure And Mechanical Properties Of Aluminum Sheet Used For Easy-Open-Can Prepared By High-Efficient Melt-Treatment Technology

Aiming at the existing problem in metallurgical quality of the aluminum sheet used for easy-open-can made in China and the current situation that the key properties of aluminum sheet can't satisfy the requirement of making can, the aluminum sheet used for easy-open-can was firstly prepared by adopting the technology of high-efficient melt-treatment in the study. The regulation of microstructure and mechanical properties of aluminum sheet used for easy-open-can in different states (as-cast, as-rolled, as-homogenization and as-mid-annealed) were studied deeply and systematically with the aid of some modem analytical and testing techniques, such as OM, ESEM, XRD, DTA and mechanical properties testing. The influence and interactive mechanism were analyzed. Compared with the aluminum sheets used for easy-open-can prepared by routine melt-treatment and produced locally or abroad, the optimal process of heat-treatment was obtained under the experimental conditions. The main conclusions are as follows: 1. The metallurgical quality of the aluminum sheets used for easy-open-can can be improved remarkably by adopting the technology of high-efficient melt-treatment. Rare earth (Re) had the obvious effect on the Fe phase and made it be short-skeleton or spherical shape, the small second phase in the interior grain precipitated evenly. Thus, the way of fracture of the material was changed. The tensile strength and the elongation of the material were increased by 16.6% and 90.2% respectively, compared with the aluminum sheets without melt-treatment. 2. The spherical shape of the second phases precipitating on the grain boundary of the aluminum sheet used for easy-open-can made by adopting the technology of high-efficient melt-treatment was more obvious. The optimal homogenization process, i.e. holding 1 215h at 450-500℃, air-cooling, was obtained, which provided the ideal uniform state of microstructure and made the second phases be round shape. The synthesis mechanical properties were superior to the properties by adopting routine melt-treatment. This process can decrease the energy during making the aluminum sheet. 3. The recrystallization temperature and velocity of forming the grain nuclear of aluminum sheet used for easy-open-can prepared firstly by adopting the technology of high-efficient melt-treatment were raised. The optimal process of mid-anneal, i.e. holding lh at 43℃, air-cooling, was obtained. The aluminum sheet had fine and uniform grains, suitable surface-hardness and mechanical properties by adopting this process. The fracture mechanism was mainly the congregation of transgranular micro-hole and the anisotropy of planar-plasticity was the lowest. 4. The metallurgical quality of the aluminum sheet used for easy-open-can prepared by adopting the technology of high-efficient melt-treatment was superior to the products produced locally or abroad. 2 and 5 were increased by 9.1%, 19.6% and 12.8% respectively, compared with that of aluminum sheet made in China. The main mechanical properties can reach or surpass the properties of the products produced abroad and fit for making can.