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在2000kN立式液压机上,将半固态A356铝合金挤压铸造成形。研究了不同的浇注温度与比压对铸件组织与力学性能的影响。结果表明,随着比压增大,铸件组织更为细小、致密、圆整,抗拉强度、屈服强度、伸长率也有较大幅度提高,但比压达到一定程度后,增加比压对铸件的组织及性能影响不明显。浇注温度过低、固相率过高导致充型困难,各部位容易出现凝固裂纹;浇注温度高时液相率过高,铸件为枝晶组织,两种情况下均不能得到力学性能较好的铸件。在582℃、48.7MPa挤压条件下能获得较好的组织与力学性能,抗拉强度、伸长率分别达到288MPa、14.6%。
In 2000kN vertical hydraulic machine, the semi-solid A356 aluminum alloy extrusion casting shape. The effects of different pouring temperature and specific pressure on the microstructure and mechanical properties of castings were studied. The results show that with the increase of specific pressure, the microstructure of the castings is more fine, dense and round, and the tensile strength, yield strength and elongation also increase greatly. However, after the specific pressure reaches a certain level, The organizational and performance impact is not obvious. Pouring temperature is too low, the solid phase rate is too high lead to filling difficulties, prone to solidification cracks in various parts; pouring temperature is high liquid phase rate is too high, the casting is dendritic, both cases can not get better mechanical properties casting. Under the conditions of 582 ℃ and 48.7MPa, good mechanical and mechanical properties were obtained. The tensile strength and elongation reached 288MPa and 14.6% respectively.