Study On The Iron-rich Phase Regulation And Melt Purification Of Recycled Aluminum

With the development of China's industry,the application of aluminum alloys has become increasingly widespread,and the total output of aluminum alloys has risen rapidly.Based on the concept of sustainable development and environmental protection,aluminum recycling and recycling has increasingly become an important issue in the aluminum alloy industry.In the aluminum recycling process,other metal elements may be involved in the aluminum melt,such as Fe,Na,Mg,Ca,etc.,where Fe element has a great influence on the performance of aluminum alloy.In addition,because there are many types of contaminants adsorbed on the surface of the recovered raw materials,if no treatment is performed during remelting,a large amount of slag,inclusions and large-sized harmful second phases will be generated during the casting process,which significantly affects the finished product.Tensile strength,elongation,airtightness and yield of castings.This subject first aims to reduce the effect of Fe element on the performance of aluminum alloy.By adding Fe element to the standard A356 alloy,the Fe-Al intermediate alloy is introduced to analyze the effect of high content of Fe element on the performance and structure of A356 alloy;The A356 alloy with an element content of 0.15%was optimized.By adding Mn element to it and using heat treatment,a reasonable and effective method to reduce the effect of Fe element on the alloy performance was found.Several morphologies of the iron-rich phase in A356 were observed and the corresponding mechanical properties were tested.When the Mn element was added so that the Mn/Fe content ratio in the sample was 0.34,the mechanical properties of the alloy were the highest,the yield strength reached 134MPa,and the extension The rate has reached 18.1%;when the solution temperature is 540?,the alloy samples of this composition have the best alloy properties.Secondly,based on actual production,using the world's most advanced online slag inclusion detection technology,ABB's PoDFA(Porous Disc filtration Analysis)system,to detect and evaluate the purification effect of aluminum melt in various links in the field production At the same time as the qualitative analysis of slag inclusions,each component of inclusions was statistically tested.Targeted improvement and optimization programs are proposed to improve the alloy melt and increase the wheel hub yield.The research content includes two aspects,one is to change the way of adding the refining agent in the melt,use nitrogen-assisted refining agent for blowing or evenly spray the refining agent on the surface of the melt.The analysis of the original aluminum liquid filter sheet shows the different effects of injection refining and covering refining on the purity of the melt,and quantitatively analyzes the effect of the two refining methods on the removal of slag inclusions;Perform standing at different times to analyze the effect of standing time on the purity of the melt.Studies have shown that although injection refining may introduce AlN slag inclusions,the total amount of slag inclusions is significantly reduced,and the filtering speed is the fastest,so it is better than the coverage refining effect.When the standing time is 60min,the total amount of slag inclusions is1.09mm~2/kg,which is 50.7%less than that when not standing.The standing time is between 120min and 90min,and the overall content of slag inclusion is not obvious.In order to improve the actual production efficiency,the standing time should be chosen as60min is the most appropriate.