返回料及精炼工艺对A356铝合金净化效果的影响

The influence of recycled material proportion on the size and content of inclusion in A356 aluminum alloy was investigated. Effects of recycled material addition on the stability of mechanical properties were analyzed by mechanical property test, and influence of rotary injection refining process parameters on density, inclusion size and content of aluminum melt were analyzed. The results indicate that with increase of recycled material proportion, the size and content of the inclusions in the alloy are increased, and the mechanical performance stability is decreased. The efficiency of degassing and impurity removal can be improved by properly increasing the rotation speed and gas flow or setting appropriate gas pressure. For A356 aluminum alloy melt with 30% recycled material, the optimized refining process parameters present as follows: Rotor speed of 500 r/min, gas pressure of 0.8 MPa and gas flow of 20 L/min. On this condition, the aluminum melt density can reach 2.657 g/cm³, and the volume fraction of inclusions can be decreased to 0.08%, satisfying production requirement.