Preparation method of Al-Zn aluminum alloy cast ingots

The invention belongs to the field of alloys, and particularly relates to a preparation method of Al-Zn aluminum alloy cast ingots. The preparation method includes the steps of a) subjecting aluminum sources, copper sources, magnesium sources, zinc sources and zirconium sources to melt blending to obtain aluminum alloy melt, to be specific, the aluminum alloy melt comprises 2.0-2.6wt% of Cu, 1.9-2.6wt% of Mg, 5.7-6.7wt% of Zn, 0.08-0.16wt% of Zr and the balance Al; b) preheating casting equipment; c) casting the aluminum alloy melt in the preheated casting equipment to obtain the Al-Zn aluminum alloy cast ingots under the cast temperature of 750-775 degrees and at cast speed of 11-45mm/min. According to the arrangement, before the aluminum alloy melt is cast, the casting equipment is preheated, casting conditions are optimized, and as shown in the experience, the crack detection pass rate of the aluminum alloy cast ingots is increased to 90% or above.