Research On Fe Distribution In Pure Magnesium Stewed Melt

Since taking advantage of magnesium and its alloys,it went through one and a half centuries.Human beings begin to use magnesium alloys products in many industries,such as automotive industry and aerospace industry.To produce higher quality of magnesium alloys products,smelting magnesium alloys is a key step.The primary materials used to smelt alloys put forward higher requirements.For this purpose,people have made a lot of research on removing Fe from magnesium alloys.In this paper,carry out the experiment and theoretical study.In the aspect of experiment,measure the precise melting point of the pure magnesium with DSC,in order to make sure the heat preservation temperature during the low-temperature layering purification.Then,do the research on the distribution of the iron particles in different heights in the magnesium melt.Use the electronic microscopy to represent the morphology,numbers and component of the particle contenting with Fe.In the aspect of theoretical study,derive the instantaneous velocity expression and the acceleration time expression to describe a single pure iron round particles accelerated motion in magnesium melt based on the formula of stokes.The iron particles distribution on the effect of gravity sedimentation in magnesium melt model is established.Put forward the relation between the round iron particles distribution and the iron concentration in magnesium melt.Then try to derive the iron concentration expression in a certain height after a certain time of the low-temperature layering purification in magnesium melt.According to the study,can draw the following conclusions:By the research of the melt at different heights,can learn the following rules:(1)Before the low-temperature layering purification,the Fe concentration in the pure magnesium melt is 99 ppm.After the low-temperature layering purification,the Fe is redistributed to three layers in different heights.In the first layer from 5 mm to 101 mm distance to the surface of the magnesium melt,the iron concentration is obviously descent compared to the original melt,from 66 ppm to 93 ppm.In the second layer from 5 mm to 101 mm distance to the surface of the magnesium melt,the iron concentration no obvious change near to 93 ppm.In the first layer from 184 mm to 253 mm distance to the surface of the magnesium melt,the iron concentration is ascent obviously compared to the original melt,from 91 ppm to 117 ppm.(2)After the low-temperature layering purification,iron particles mainly take the following form in magnesium melt: a)square particle contenting Mg,Fe and Si;b)round particle contenting Mg,Fe,Mo and O;c)out-of-shape particle contenting Mg,Fe and O;d)bar particle contenting Fe.(3)In the aspect of theoretical study,derive the iron concentration expression in a certain height after a certain time of the low-temperature layering purification in magnesium melt,based on the research on a single round iron particle gravity sedimentation in magnesium melt.The expression is as the follows(4)According to the gravity effects on different typical of irons,a more refined formula can be calculated,which can be used to estimate the result of the gravity sedimentation,the expression is as the follows...