Aluminum die-casting of time to pay attention to what matters?​

Aluminum die-casting of time to pay attention to what matters?

Alloying element in aluminum alloy dissolution add elements dissolved in the molten aluminum is alloyed important process. It is closely related to its dissolution properties of the elements, destruction and atomic structure by adding the binding force of the solid elements in liquid aluminum diffusion speed control.

     Dissolution of the elements available in liquid aluminum elements and aluminum alloy phase diagram to determine, generally and aluminum eutectic fusible element is easily dissolved; and aluminum peritectic transformation, particularly the melting point of very different elements of difficulty dissolved. Such as Al-Mg, Al-Zn, Al-Cu, Al-Li as the eutectic alloy system, which are also close to the melting point of aluminum, alloying elements dissolve more easily in the smelting process can be added directly to molten aluminum; However, Al-Si, Al-Fe, Al-Be alloy system, etc., although there are also eutectic reaction, due to the larger difference between the melting point of aluminum, is very slow to dissolve, require a larger superheat to complete dissolution; Al-Ti, Sl-Zr , Al-Nb and so has peritectic type phase diagram, are considered insoluble metallic elements dissolved in aluminum is very difficult, in order to dissolve as soon as possible in aluminum, it must be added to the master alloy form.
     The evaporation of the evaporation element physical phenomenon is always present in the smelting process. Metal evaporated (or volatilized), depending on the size of the vapor pressure. In the same melting conditions, high vapor pressure element is easy to evaporate.
 
      Can add elements into the aluminum vapor groups, Cu, Cr, Fe, Ni, Ti, Si and other elements of pressure than aluminum small, slow evaporation; Mn, Li, Mg, Zn, Na, Cd and other elements aluminum vapor pressure than larger, easier to evaporate, the larger losses in the smelting process. Acting metal smelting furnace gas and aluminum die-casting process, the metal is molten or semi-molten state is exposed to the gas furnace and a long time of interaction, it often causes a lot of inspiration metal oxide, and other non-metallic inclusions are formed.
 
Factors affecting gas content
 
(1) the impact of the gas alloying element binding force larger alloying elements such as titanium, zirconium, magnesium alloys will increase the gas solubility. And copper, silicon, manganese, zinc and other elements can reduce the solubility of aluminum in the gas.
 
(2) The gas partial pressure at a temperature the same conditions, gas solubility in the metal with the furnace gas composition in the hydrogen partial pressure increases. Therefore, the flame furnace smelting aluminum melt furnace in hydrogen solubility than large.
 

(3) the effect of temperature when the hydrogen partial pressure is constant, the higher the temperature of the aluminum melt the more hydrogen uptake. Furthermore, the metal surface oxide film state and melting time for gas solubility in aluminum melt also affects

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