Influences of different degassing processes on refining effect and properties of 4004 Al alloy

In order to improve the plasticity of 4004 Al alloy and subsequently the productivity of 4004 Al foil, the research studied in detail the influence of the rotary impeller degassing process on the refining effect of 4004 Al alloy, in which the impacts of four major parameters: gas flow, rotational speed, refining time, and stewing time, on degassing rate of 4004 Al alloy was systematically studied by using an orthogonal experiment methodology. Results show that the rotational speed has the greatest impact on the degassing of 4004 Al alloy, followed by gas flow and refining time; stewing time has the least impact. The optimum purification parameters obtained by current orthogonal analysis were: rotor speed of 500 r·min-1, inert gas flow of 0.4 mL·h-1, refining time of 15 min, and stewing time of 6 min. Degassing rate using the optimum parameters reaches 68%. In addition, the comparison experiments among C2Cl6 refining, rotary impeller degassing, and combined treatment of C2Cl6 refining and rotary impeller degassing for 4004 Al alloy were performed. The experimental data indicated that the combined treatment of C2Cl6 refining and rotary impeller degassing has the best degassing effect. Degassing rate of C2Cl6 refining, rotary impeller degassing and combined refining treatment is 39%, 69.1% and 76.9%, respectively. The mechanical properties of the specimen refined by rotary impeller degassing were higher than those by C2Cl6 refining, but lower than those by combined refining treatment.

Rotary impeller refinement of 7075Al alloy

The effects of four parameters, gas flow, rotational speed, refining time, and stewing time, on the rotary impeller refinement of 7075 Al were studied. The effects of C2Cl6 refining, rotary impeller refining, and composite refining of 7075 Al alloy were compared with each other. The results showed that the greatest impact parameter of rotary impeller refinement was rotational speed, followed by gas flow, refining time, and stewing time. The optimum purification parameters obtained by orthogonal analysis were as follows： rotor speed of 400 r/min, inert gas flow of 0.4 mL/h, refining time of 15 min, and stewing time of 6 min. The best degassing effect can be obtained by the composite refining of C2Cl6 and rotary impeller. The degassing rate of C2Cl6, rotary impeller, and composite refining was 34.5%, 69.2%, and 78%, respectively. The mechanical properties of the specimen refined by rotary impeller were higher than those by C2Cl6 refining, but lower than those by composite refining.