In addition to meeting the working performance requirements of the parts made, die-casting aluminum alloy should also have the following properties in order to be able to perform pressure casting smoothly:
(1) When the degree of overheating is not high, even in the solid and liquidus temperature range, it should have good plastic rheological properties, that is, under pressure, the seemingly viscous aluminum alloy liquid still has excellent The fluidity makes it easy to fill complex cavities to ensure good surface quality of die castings. Reduce shrinkage holes in the castings. At the same time, improve the working condition of the die-casting mold and increase its working life;
(2) The linear shrinkage rate is small, and there is a certain high temperature strength, so as to avoid cracks and deformation of the casting, and improve the dimensional accuracy of the casting;
(3) The small crystallization temperature range can reduce the possibility of shrinkage holes in the casting;
(4) It has a fixed high temperature solid strength to prevent deformation or cracking of the casting when the mold is opened; (5) It should have a certain strength at room temperature to maximize the mechanical strength and surface hardness of the die casting;
(6) There is no chemical reaction with the die-casting mold, and the affinity is small to prevent the sticky mold from alloying with the casting and the mold;
(7) It is not easy to inhale and oxidize in the high temperature molten state, so as to meet the requirements of long-term heat preservation during die casting.