真空度对真空压铸镁合金副车架品质的影响

Effects of Vacuum Level on Appearance and Internal Quality of Die Cast Mg Subframe

对比研究了真空压铸中低真空(20~30 kPa)与高真空(<5 kPa)对AE44镁合金副车架铸件外观与内部品质的影响。结果表明,与低真空压铸相比,高真空压铸能够显著减少镁合金副车架表面压铸流痕、冷隔以及内部的气孔类缺陷、提高镁合金副车架本体试样的室温塑性和抗拉强度及其致密度,并降低孔隙率,其中铸件本体试样室温伸长率增幅接近50%,平均密度提高了0.51%,孔隙率均值下降了0.50%。压铸中采用高真空(<5 kPa)能够有效地提高镁合金副车架的致密度,从而显著提高铸件的抗拉强度和伸长率。

The effects of vacuum level on the appearance and internal quality of die cast AE44 Mg subframe castings were investigated.The results show that compared with low vacuum(20~30 kPa),high vacuum(<5 kPa)can significantly reduce the flow marks/cold shuts on the surface of castings and the gas hole defects in the castings,improve the elongation and tensile strength at room temperature,increase the density and reduce the porosity of the castings.The elongation of the magnesium alloy subframe is increased about 50%,and the average density is improved by 0.51%with the average porosity decreased by 0.50%.High vacuum die casting(vacuum level<5 kPa)can effectively improve the density of Mg subframe castings,which further significantly improves their tensile strength and elongation.