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  • Main reasons for the appearance of pores in molten casting aluminum alloy
  • Editor：Hangzhou Hongcheng Pml Precision Mechanism LtdDate：2015-12-21 16:11 Click：
high strength cast aluminum alloy high strength cast aluminum alloy , aluminum sand mold and so on.
    molten mould casting aluminum alloy parts sometimes have air blowholes, and the main reason is that the higher the melting temperature, the metal liquid sucked hydrogen from the moist air, and the main source of hydrogen was due to the decomposition of water vapor under the high temperature of the aluminum liquid. The solubility of hydrogen in aluminum liquid is higher with the increase of temperature, but the solubility of hydrogen in solid aluminum is very low. Therefore, during the solidification process, the porosity formed by hydrogen precipitation has a great relationship with the melting temperature and melting time of the alloy. In the later period of melting, if the control is not appropriate, if the temperature is too fast and too high, the amount of hydrogen absorption in the aluminum liquid is larger, the more the hydrogen diffuses in the aluminum liquid, the more the chance of the pinhole appears. The hole on the outer surface is less because of the rapid cooling.
    it is reported that at 700 C, the solubility of hydrogen in every 100g aluminum is 0.5 ~ 0.9, and the solubility of hydrogen increases by 2~3 times when the temperature rises to 850. Melting should be controlled below 750 degrees, and fast melting should be advocated. However, it is also necessary to control the problem of excessive speed at the later stage of heating up.