Separating Process And Structure Of 434 Al Alloy Composite Sheet

Transfer exchangers of the 434(4004/3003/4004)aluminum(Al)alloy composite sheets are extensively used in certain industries,including automobiles,household appliances,and aerospace components.The one reason why is that has a core layer(3003 Al alloy)with good plasticity and corrosion resistance.As well as the second reason why is that has a clading layer(4004 Al alloy)with high temperature strength,high temperature corrosion resistance,good wear resistance,and low thermal expansion.Because the core layer differs from the cladding layer of composite sheet in the main chemical composition,resulting in recycling’s method of composite sheet that is relatively single at present.Composite sheet can only be recycled in the remelting fulfill,necessitating a high heating temperature that leads to severe loss of alloy elements.Whereas,alloy’s recovery after separation,only needs a lower heating temperature and a minor loss of alloy elements.This thesis utilizes difference of melting point between the clad and core layer of the composite sheets that achieve them separateness,in which heating in air and master liquid medium,respectively.This thesis selected the 434 Al alloy composite sheet as raw material and solved the thermal physical parameters of 4004 Al alloy,3003 Al alloy and liquid of master(4004 Al alloy)by Jamatpro software.The temperature field was simulated by the steady state and transient heat transfer modules in ANSYS software.The Fluid Flow(Fluent)module was simulated the temperature field,liquid fraction,etc.During the434 Al alloy composite sheet heated and melted by the method of selecting a master as liquid.The situation of separating the 434 Al alloy cladding layer alloy was analyzed by separating the cladding layer 4004 Al alloy and the core layer 3003 Al alloy using melting directly method(melting directly method)and master’s liquid melting method(the method of choosing a master as liquid).The effect of process parameters on quality,macroscopic size and oxidation status under the condition of master liquid was analyzed.The chemical composition of the master liquid alloy ingots was tested by a reading directly spectrometer.The microstructure,solute distribution and phase of the coating layer,a core layer and a diffusion layer of the melting directly method and the method of choosing a master as liquid samples were studied using optical microstructure(OM),X-ray diffraction XRD,scanning electron microscopy(SEM),etc.The optimal process for recovering 434 Al alloy was employed.Simulations and text results of the melting directly process demonstrate that the434 Al alloy composite would be heated and held at a rate of 6 ℃/s for 200 seconds in600 ℃ air,with no minimum temperature global and confined temperature field above approximately 600 ℃,which is equivalent to the behavior described for an altimeter.The 434 Al alloy composite sheet preheated at 350 ℃ for 1 hour,after holding at 600℃ for 2 hours.The median thickness of layer 4004 is 957 μm.Median thickness of3003 layers is 1581 μm.The minimum thickness is 879 μm.The median thickness of the diffusion layer is 33 μm.The separation of the coating layer alloy can be reached,while require considering the erosion of the core layer.The simulation and text results of the the method of choosing a master as liquid,indicating that the simulation results of the coating layer have transformed into a 600℃ for 5 seconds and the temperature field is uniform at 1800 seconds,with all the coating layers becoming liquid phase.Keep the master liquid at 590-600 ℃ for 4minutes,and as the heating temperature or holding time increases,the thickness of the cladding layer of the composite board first increases and then decreases.As the liquid temperature of master increased from 596 ℃ to 600 ℃,holding about 4 minutes.At this time,the median thickness of coating layer first decreases to 1/3 of the original sample,which is the minimum thickness of 101 μm.The diffusion layer has 29 μm.Core layer thickness has 3405 μm.After 6-7 minutes,the 4004 Al alloy has a well effect of removal,less oxidation situation and good quality of surface.The method of choosing a master as liquid indicates that the melting of alloy is divided four stages:surface solidification,surface was melting,element diffusion and core layer was melting.The best condition of master liquid at 600 ℃ for 7 minutes,which the median thickness of the coating layer,the core layer and the diffusion layer is 334 μm,2453μm,17 μm,respectively.