The hydrogen content and nonmetallic impurities of aluminum alloy in melting and casting workshop will seriously affect the quality of castings. Usually, in the condensation process, with the decrease of hydrogen solubility, hydrogen can not escape from the solution, and the nonmetallic magazine can not float to the liquid level before entering the mold, which will lead to the increase of white spots and pinholes on the surface of plates and foils in the subsequent rolling process, resulting in the decline of mechanical properties of materials, and eventually lead to the scrapping of products. Therefore, it is necessary to take mesures for Degassing Molten Aluminum.
Degassing Process In Aluminium
The working principle of degassing box is that inert gas does not react with molten aluminum and is insoluble in molten body at casting temperature. Through the high-speed rotating graphite shaft, it is blown into the liquid aluminum to form a large number of continuous small bubbles.
When the inert gas bubble rises from the bottom of the cavity, the hydrogen in the melt will continue to diffuse to the bubble due to the existence of pressure difference. After the bubble rises from the liquid surface, hydrogen in the bubble escapes into the atmosphere. In the process of bubble floating, when non-metallic inclusions are encountered, they will adhere to the surface of bubbles due to the effect of surface tension, and these inclusions will be eliminated with the rising of bubbles. At the same time, the filter media in the filter chamber will further block the inclusions, so that the magazine precipitation is blocked in the filter medium, so that the aluminum liquid can be completely purified. A filter box can be used to remove impurities. Plate filter box is the necessary equipment for continuous casting and semi continuous casting filter purification system to form a stable filtration.