Refining method of aluminum-magnesium-series cast aluminum alloy material

The invention relates to a refining method of an aluminum-magnesium-series cast aluminum alloy material. In the method, a novel covering agent is selected for performing surface protection on an aluminum-magnesium-series alloy in a smelting process, a refining agent special for a magnesium-aluminum alloy is prepared simultaneously for refining a melt, and the smelting temperature and the pouring temperature are controlled, so that an aluminum-magnesium-series cast aluminum alloy with higher performance and a low magnesium burnout rate is obtained. According to the method, the novel covering agent and the special refining agent are applied for smelting an Al-Mg-series alloy (the content of Mg is 3-10 percent) under the control of a specific production process, so that the burnout of magnesium is controlled effectively, the production cost is saved, the cleanliness of the alloy is enhanced, and the porosity of the alloy is lowered.