The invention relates to an aluminum
alloy for a special high-pressure
oil pump shell and a preparation method thereof. The
alloy comprises the ingredients by weight percent: 5-7% of Si, 1.3-1.7% of Cu, 0.4-0.7% of Mg, 0.1-0.35% of Mn, 0.2-0.3% of Ti, 0.4% or less of Fe, 0.01% or less of Sn, 0.01% or less of Pb, 0.03% or less of Ca, 0.05% or less of single
impurity, and the balance of aluminum, wherein the total impurities are 0.15% or less. The preparation method comprises the following steps of:
smelting at 755-765 DEG C; spraying a common refining agent by
argon at 745-755 DEG C; evenly scattering a
sodium modifier under the temperature which is 740 DEG C at least, standing for 10-20 minutes;
casting by a semi-continuous direct
water cooling method; homogenizing a cast
ingot, naturally cooling after discharging from a furnace; and carrying out heat treatment
quenching after extruding and molding the homogenized cast
ingot, and finally carrying out
precipitation heat treatment. The aluminum
alloy has the beneficial effects of good high temperature performance, thermal deformability,
abrasive resistance, gas tightness and the like, is good in
casting and extruding properties, and can be well applied to the special high-pressure
oil pump shell.