{"id":8420,"date":"2022-01-13T07:36:12","date_gmt":"2022-01-13T07:36:12","guid":{"rendered":"https:\/\/www.aluminiumceramicfiber.com\/?p=8420"},"modified":"2022-01-13T07:36:52","modified_gmt":"2022-01-13T07:36:52","slug":"aluminium-foundry-degassing-device","status":"publish","type":"post","link":"https:\/\/www.aluminiumceramicfiber.com\/ar\/aluminium-foundry-degassing-device\/","title":{"rendered":"Aluminium Foundry Degassing Device"},"content":{"rendered":"

Aluminium Foundry Degassing Device removes impurities from the melt to provide a cleaner, better quality metal.<\/span> It is one of the most common and effective cleaning methods in foundries.<\/span><\/p>\n

Two main impurities are found in liquid aluminum: dissolved hydrogen and non-metallic inclusions.<\/span> As the metal cools, dissolved hydrogen escapes from the solution and forms harmful pores.<\/span> Such porosity and non-metallic solid inclusions can reduce the strength of aluminum castings and adversely affect the final properties.<\/span><\/p>\n

Therefore, Aluminium Foundry Degassing Device must be used to remove dissolved hydrogen and non-metallic inclusions in the aluminum solution before casting to achieve the best quality.<\/span><\/p>\n

Processes developed for cleaning metals are physical processes that involve the use of inert gas fluxes.<\/span><\/p>\n

Hydrogen dissolved in the molten material diffuses into rising bubbles of flux gas and is transported to the surface of the molten material.<\/span> This process depends on two main steps:<\/span><\/p>\n

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  1. The rate at which hydrogen diffuses through the diffusion boundary layer into inert bubbles.<\/span><\/li>\n
  2. Hydrogen concentration in inert bubbles.<\/span><\/li>\n<\/ol>\n

    Diffusion is the deterministic stage of degassing rate.<\/span> Therefore, in order to achieve optimal degassing efficiency, the following requirements must be met:<\/span><\/p>\n

    Inert gases have smaller bubbles and stay in the molten metal longer.<\/span> This ensures a large surface contact area between inert bubbles and the molten metal, thus ensuring a higher mass transfer coefficient relative to the diffusion layer.<\/span><\/p>\n

    \"Aluminium<\/p>\n

    Aluminium Foundry Degassing Device rotating impellers work by increasing the surface area of inert gases introduced into the metal. <\/span>The smaller nitrogen bubbles produced by the impeller process have a larger total surface area and collect more hydrogen.<\/span><\/p>\n

    The lower surface disturbance of the smaller bubbles also allows less hydrogen to be recaptured into the metal from atmospheric moisture.<\/span><\/p>\n

    Aluminum degassing<\/a> process in casting, inert or chemically inert gases (argon, nitrogen) are removed by rotating shafts and rotors.<\/span><\/p>\n

    The energy of the rotating axis leads to the formation of a large number of small bubbles, which provide a very high surface-to-volume ratio.<\/span><\/p>\n

    The large surface area promotes the rapid and efficient diffusion of hydrogen into the bubble, thus balancing the activity of hydrogen in the liquid and gas phases.<\/span><\/p>\n

    A rotary degassing machine can remove hydrogen more thoroughly than flux degassing.<\/span><\/p>\n

    In addition, rotary degassing machines do not use harmful chlorine and fluoride salts.<\/span><\/p>\n

    Rotary degassing machine can also combine degassing and flux introduction functions.<\/span><\/p>\n

    In this case, the inert gas acts as a carrier for the particle flux.<\/span> This method is called flux injection.<\/span><\/p>\n