Combined flame-retardant and anti-oxidation method for 3DP (three-dimensional printing) sand mold magnesium alloy casting

The invention relates to a full-process combined flame-retardant and anti-oxidation process for 3DP sand mold casting of a magnesium alloy casting, which is characterized in that a self-flame-retardant 3DP sand mold, sand mold flame-retardant coating/layer coating, melt mechanical filtration and casting pouring and solidification under the atmosphere protection condition are jointly applied to 3DP sand mold casting production of the magnesium alloy casting, so that oxidative combustion of a magnesium alloy melt in the pouring process is prevented; inclusions in the casting are reduced, and the product quality and yield of the magnesium alloy casting are improved. The oxidative combustion tendency of the melt in the obtained casting mold is remarkably reduced, defects such as oxide nodules and burning points on the surface of the casting are reduced, oxide inclusions in the casting are reduced, the surface and internal quality of the casting is improved, and the qualification rate of the casting is increased.