The vacuum degassing die-
casting process method comprises the following steps that S1,
smelting and degassing are conducted, specifically, an aluminum
alloy raw material is smelted and subjected to heat preservation for 30 minutes,
inert gas is introduced through a rotary degassing
machine in a gradient variable-speed mode, the gas flow is 15-20 L / min, and the operation lasts for 8-12 minutes; s2, mold pretreatment is conducted, specifically, a water-based
release agent is sprayed, the temperature of the mold is controlled to 200-250 DEG C through multi-section pulse type heating, and a double-channel vacuum valve is arranged in a mold sealing groove; s3, vacuum
die casting: starting a vacuum
system after die
assembly, enabling the vacuum degree of a die cavity to be less than or equal to 50mbar and maintaining for 3 seconds, and adopting three-stage injection control; and S4, post-treatment is conducted, specifically, after pressure maintaining is conducted for 8-12 seconds, mold opening is conducted, and graded water-cooling
quenching is conducted on the
casting immediately. The design of gradient variable-speed degassing and the double-channel vacuum valve is adopted, the
hydrogen content of a
casting is remarkably reduced, and the requirement for the long fatigue life of an automobile structural part is met; the multi-section pulse heating greatly improves the heating speed, obviously reduces the unit
energy consumption, reduces the
thermal fatigue of the mold, and prolongs the service life.