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.
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