Casting A356 aluminum alloy has been widely used in products such as automobiles and motorcycles due to its excellent casting properties, heat treatment properties, processing properties and mechanical properties, and has become one of the most important AI-Si series cast aluminum alloys. The main defects of cast aluminum alloy-pores and slag inclusions are caused by solid particles such as gas and oxides remaining in the alloy. Therefore, in order to obtain high-quality melt, it is not only necessary to select the correct and reasonable smelting process, but also the refining and purification treatment of the melt is also very important. Smelter Aluminum Flux Purification is the key to improving the quality of aluminum alloy metallurgy, and it is also the basis for refinement and deterioration.
In the metallographic structure of A356 aluminum alloy without melt purification treatment, large blocky inclusions appear, needle-like eutectic silicon phase appears in the microstructure, and rod-like dendrites are coarse. In the metallographic structure after the smelter aluminum flux purification treatment, the inclusions are significantly reduced, the inclusions are fine and dispersed, and the fine dendrites are evenly distributed. The refining flux treatment has a high impurity removal rate and a good hydrogen removal effect. The hydrogen content in the molten aluminum after the refining flux purification treatment becomes less. It can be seen that the refining flux treatment of A356 aluminum alloy has a good degassing and impurity removal effect, which also indicates that the inclusions in the molten aluminum play an important role in the formation of pores.
The Influence of Refining Time on Smelter Aluminum Flux Purification
During the holding time from 10 min to 3 h, with the prolonging of holding time, the impurity content and hydrogen content of molten aluminum after flux treatment increased to varying degrees. The impurity content and hydrogen content of the molten aluminum after the flux purification process changes relatively smoothly with the extension of the heat preservation and standing time.
In summary, with the prolongation of the heat preservation and standing time, the gas content of aluminum ingots is constantly increasing. Therefore, the heat preservation and standing time of the flux purification treatment of A356 aluminum alloy should generally be controlled within 10-40 min. The impurity content of the molten aluminum after the flux purification treatment is significantly reduced, and the hydrogen content of the molten aluminum changes slightly with the extension of the heat preservation and standing time. It shows that the purity of molten aluminum (the content of inclusions) has a certain effect on the hydrogen content of the molten aluminum after different standing times, and further illustrates the interdependence between impurities: less impurities, less hydrogen content.