The Study On The Elimination And Modification Of Iron Impurity In The Cast Aluminum Alloy

As a natural impurity elements in aluminum alloy, iron is easy to enrich, which reducethe sustainable quality of aluminum during the melting and recycling process of aluminum. Inaluminum alloy especially casting aluminum alloy, iron is apt to form needle phase combinedwith other elements, resulting in failure of the aluminum alloy parts. There are many effectivefluxes for removal of various elements in aluminum alloy in aluminum industry, but IronRemoving Flux is still blank. Accompanied by the rise of recycled aluminum industry, lots ofresearch focused on iron removing technology, only the sorting methods getting applications.Effective methods to remove Fe in aluminum alloy have been reported on academic literatures,without applications in casting room. In this paper, we select several different castingaluminum alloy with specific iron content, expecting a best effect on the process of ironremoving through the optimization of the alloy component and production process.In this paper,the Mn flux is added as a main composition with Mg,characterized by ICP、OM、SEM/EDS and XRD, to investigate the action of remove of iron in cast aluminum alloy,modification of iron phase and the relationship between the morphology of iron phase andiron removal efficiency.The results show that:(1) Under the die casting condition, the method of combining adding Mn with gravitysettling to remove Fe has been studied in aluminum alloy with1.5wt.%Fe and trace of silicon.There exists an optimal Fe/Mn (in this work Fe/Mn is1:3), which has a optimistic effect onthe iron removal efficiency and the residual rate of Mn.(2)Cooling conditions have a greater impact on needle iron phase of casting aluminumalloy; with the same element content of Si, the needle phase sharply grow as the Fe contentincreases; while at the same Fe content, as the element of silicon increases, the number of ironphase increase and become more coarse.(3) The action of adding Mn elements change the morphology of the Fe phase, which isthe results of Al6Mn dissolve Fe forming AlMnFe phase. And which make the needle-like ironmorphology become more particular like hollow-block, Chinese script type; Based on which, the adding of Mg elements didn’t change the morphology of iron phase, but played a role ofdissolving the iron phase and crushing the needle-like and bulk iron phase. Besides, theaddition of RE purify the melt and reduce the volume fraction of iron phase.(4) Primary Iron phases like needle-like, flaky and branchlike overlap each other intospace sticks mesh "filter" irregular morphology in aluminum melt, blocking larger lump andpreferentially allowing only iron phase, of which the particle size is small and the surface isrelatively smooth, passing through to settle to the bottom of the melt; while small deposits aremore dense and reduce the thickness of the deposited layer, have a higher efficiency of iron.