The Affect Of Hydrogen Content On Detecting The Compactability Of Aluminum Alloys Molten

In this thesis, based on the pressure-reduction solidification sample density method, a series of experiments have been made to gain the relationship between the hydrogen content in aluminum alloys melt and the alloy compactness, and analyze the relationship between the alloy compactness with the casting mechanical properties.The experimental results showed that, the higher hydrogen content of aluminum alloy melt, the lower of the compactness of aluminum alloy. Along with the smelting temperature's markup and soaking time's lengthen, the aluminum alloy compactness drops, when the smelting temperature is higher than 800℃, the porosity growth rate increases obviously. When soaking time is between 60~100min, the extent of the porosity growth is greater. The alloy nature, solidification rate and the negative pressure establishment's time affect greatly to the casting's cavity size and the distribution. At the same time, it can create certain errors by adding some kind of alloying element when using the density method to examine the aluminum alloy compactness. The casting mechanical properties decrease along with the compactness depresses. The heat treating can obviously enhance the casting mechanical properties, but it cannot eliminate the influence of the inclusion.Meanwhile, this paper showed the accuracy of using the pressure-reduction solidification sample density method to examine the hydrogen content in aluminum alloy melt by contrastive analysis of the sand samples and the pressure-reduction samples. And we can realize the hydrogen content semi-quantitative online examination by the comparison of the sample density and the porosity rate. In the aluminum alloy melt solidification process, the outside pressure and the solidification temperature range have some influence on using the pinhole degree rank method to examine the hydrogen content in aluminum alloy melt. It is more precise when the outside pressure is low. It is found by the analysis between the sand samples and the pressure-reduction samples that when testing hydrogen content of alloys. The shrinkage porosity formed by the casting is of little effect with the pressure-reduction solidification sample density method.