Effect Of Tooling Materials On The Purity Of Magnesium Alloy Melt

China’s magnesium reserves are very rich,and the annual magnesium output is also very high.Although magnesium alloy has many advantages,its industrial application volume is far less than steel and aluminum alloy,which is mainly subject to its low absolute strength,poor corrosion resistance,high production costs,etc.One of the main reasons for the poor corrosion resistance of magnesium alloys is that their purity is not sufficient.Especially the elements such as Fe,Ni and Si can significantly deteriorate the corrosion resistance and mechanical properties of magnesium alloys.The existing equipment and tools in the production of magnesium alloys are made of steel.The elements such as Fe,Ni,Si are the main elements or permanent elements of the steel material.In the process of magnesium alloy casting and hot deformation,whether these steel tools will pollute the magnesium alloy melt and how to pollute,there are few reports.Under the current industrial production technology conditions,Ni in the magnesium alloy has not been well removed,although the subsequent refining means can remove most of the Fe in the melt,but not only significantly increases the production cost of the magnesium alloy,but also it will cause damage to the ecological environment,this affects the development and application of magnesium alloys.In the current commercial application of magnesium alloys,the application volume of cast magnesium alloys is much larger than that of wrought magnesium alloys.In this study,the most widely used AZ91 D magnesium alloy and AM50 A magnesium alloy are studied.Firstly,a series of thermodynamic calculations are used to analyze the effect of the main elements in the tool materials on the purity of the magnesium alloy melt,combined with the theoretical calculation results,design a series of smelting verification experiments,and then through the detection and analysis of the smelting test samples,statistics of the tools material on the magnesium alloy melting during the experimental process.Combined with the results of theoretical calculation and experimental verification,summarizes the influence of tooling materials on the purity of magnesium alloy melt,and provides corresponding basis for the optimization of magnesium alloy smelting process and the optimization of tooling materials.This study found that Mn has an inhibitory effect on the solubility of Fe in the magnesium alloy melt,and Mn inhibits the solubility of Cr in the magnesium alloy melt.At the same time,this study found that Al to Ni in magnesium alloy Solubility has an inhibitory effect;in addition,it has been found that the tool steel has less influence on the content of Fe,Ni and Cr in the magnesium alloy melt below 680 ℃,mostly in the content of the melting fluctuation or small increase,when the temperature is higher than 720 ℃,the content of Fe,Ni and Cr in the magnesium alloy melt is greatly increased,and the higher the temperature,the greater the increase;at the same time,it is found that 20# steel,H13 steel,high CrNi heat resistant steel,20# steel’s impurity element Fe in the magnesium alloy melt has the greatest influence,and the Fe content in the melt increases most.The high CrNi steel has the greatest influence on the content of Cr and Ni in the magnesium alloy melt,especially at higher temperatures.The content of Cr and Ni in the melt is greatly increased.Therefore,this study suggests that in the production and preparation process of magnesium alloy,in order to reduce the influence of the tool steel on the purity of the magnesium alloy melt,the production should be processed below 680 ℃.At the same time,the H13 steel with minimal impact on the purity of magnesium alloy.