Purity of Aluminum | Degassing Of Aluminum Alloy

Al-Si alloy has many inherent advantages, which determine its increasingly important position in the industry and more and more extensive applications. However, the main defects such as pores, inclusions and impurities in aluminum seriously affect the quality of aluminum alloy and its products. Especially for some high-performance aluminum applications, the impact of these defects becomes more prominent. With the development of science and technology and industrial production, especially the development of aviation, aerospace, electronics industry, etc., higher and higher requirements are put forward for the purity of aluminum. In order to effectively improve the purity of aluminum, the aluminum melt must be purified.

Purity of Aluminum

According to research and analysis, the main gas composition in molten aluminum is hydrogen (about 80%-90%), and the rest are nitrogen, oxygen, and carbon monoxide. The gas content in molten aluminum mainly refers to the hydrogen content. The hydrogen is mainly derived from the reaction between molten aluminum and water vapor. Any tools, fluxes, etc. used in the production, even though they are dried, are still moist compared to the molten aluminum, and will make them absorb hydrogen. Hydrogen exists in molten aluminum in two ways:

  1. More than 90% of hydrogen is dissolved in aluminum in the atomic state to form dissolved hydrogen. This type of hydrogen is difficult to remove in molten aluminum, often causing defects in ingots, and seriously affecting the performance and quality of aluminum alloy products.
  2. The remaining 10% of hydrogen is adsorbed on the surface of inclusions or gaps in the form of molecular bubbles, which is called adsorption type.

The gas in aluminum is mainly hydrogen, and hydrogen forms pores when aluminum solidifies. Due to the existence of pores, the continuity of the material is greatly destroyed, making the material appear obvious anisotropy, and its mechanical properties such as tensile, impact, fatigue, and pressure resistance are significantly reduced, and the electrical conductivity of the material is also reduced. And because of the existence of diffuse pores, it will cause loose tissues, reduce the compactness of the material, and make the material scrap due to insufficient pressure resistance.  The degassing equipment produced by AdTech is specially used for the purity of aluminum.

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