Copper pipe suction casting method for remarkably refining hypereutectic aluminum-silicon alloy primary silicon particles

The invention discloses a copper pipe suction casting method for remarkably refining primary silicon particles of hypereutectic aluminum-silicon alloy, which comprises the following steps of: firstly, smelting the hypereutectic aluminum-silicon alloy by using a resistance furnace, controlling the temperature of a melt by using a thermocouple and a controllable temperature controller, and degassing, deslagging and refining after the alloy is melted down; and then carrying out heat preservation treatment when the melt is cooled along with the furnace to be close to the set temperature of 580-660 DEG C, then carrying out differential pressure suction casting sampling by adopting a copper pipe at the set temperature of 580-600 DEG C, and then naturally cooling and solidifying the copper pipe sucking the melt in air to obtain an alloy sample. The method has a good refining effect on a primary silicon phase appearing in the hypereutectic aluminum-silicon alloy, and primary silicon particles which are small in size