Aluminum ingots, whether slabs or ingots, often have problems of porosity and porosity defects in their production. Stomatal and porosity are often associated with twin sisters and cause a lot of hassle for aluminum processing. Aluminum Alloy Ingot in the presence of circular holes known as stomatal. It is the liquid metal in the cooling and solidification process, the precipitation of gas remaining in the ingot bubble formation defects. Loose aluminum alloy ingot in the solidification process, due to the aluminum alloy in the liquid and solidified state, the volume of shrinkage can not be well replenished and produce scattered holes. Stomatal formation of the main factors: dissolved in the melt gas is saturated, there is a large number of non-metallic slag melt inclusions, the gas in the casting process of floating slow, then the bubbles will stay in the ingot to produce pores. Stomatal causes: 1. Raw materials wet. Oil. Moisture. 2. Furnace overhaul or repair. Long-term shutdown after the drying is not complete. 3. The melt overheated in the furnace. Melting time is too long. 5. Tools thoroughly dry at the end. 6.Lube oil quality is not good .7 gas water is too large. Loose generally divided into two kinds: one is shrinkage between the loose, one is to remove the formation of dissolved gas loose. The formation of looseness is mainly due to the gas content of the melt and the size of the excess tape during ingot formation, shape and structure. In the analysis of loose reasons there are several situations: 1. The melt gas content is too high; 2. Melt overheating; 3. Oven is not complete. Shut down time is too long; 4. Ling small cooling strength. Casting too fast ; 5. Foundry temperature is too low; 6. Tools and refining gas. Solvents and other wet or not; 7. Funnel for uneven flow; 8. High magnesium alloy coverage is not good.