In the liquid state, aluminum alloy reacts with moisture in the air to form Al2O3 and H2. This Al2O3 has a loose structure and a specific gravity similar to that of aluminum. It is easily suspended in aluminum liquid and has a strong adsorption effect with H2, which can be formed Adsorption core. Recycled aluminum that is widely used in the O-melting of die-cast aluminum alloys will inevitably cause hidden dangers if the pretreatment is not standardized. This point is very strict and standardized in the pretreatment of recycled aluminum when the author inspects the Japanese company Guangzhou Honda’s molten casting production. deep impression! The Si element in the Al-Si alloy is the main element. It is not only more than twice the melting point of aluminum, but also lighter than aluminum.
Therefore, in order to make it uniform during melting, strong stirring at high temperature is necessary, and gas is involved It is also inevitable to cause oxidation. In addition, the addition of Si element reduces the solubility of H2 in the aluminum liquid, and the viscosity and surface tension also increase, which hinders the formation and floating of bubbles in the aluminum liquid.
These are Al-Si system die casting
The reason for the formation of hole defects in alloy castings is that special attention is paid to the alloy refining process of the aluminum alloy smelting squadron. The previous concept was degassing. Many failure analysis of defects show that the refining process is now treated by purification, that is, the refining process. Degassing and slag removal are required for the alloy, otherwise, the result will be twice the result with half the effort, and the purification treatment of the alloy will be further optimized.