Research On Transverse Welds Of Hollow Aluminum Alloy Profile Of Continuous Extrusion

Due to the advantages of high strength,light weight,and corrosion resistance,aluminum alloy profiles can meet the light weight demand of the transportation industry.During continuous production of hollow aluminum alloy profiles,the interface two adjacent billets forms transverse weld in the profile.If this section cannot be precisely cut,the transverse weld and the skin inclusions around it will affect the normal use of the profile.Therefore,it is necessary to precisely predict the distribution of the transverse weld area,to study the welding mechanism and the nature of transverse welds for aluminum alloy profiles.In this study,a aluminum alloy hollow profile used train equipment cabin beam is chosen to study the distribution of the transverse weld during the extrusion process by numerical simulation method.At the same time,in order to reveal the formation mechanism of transverse welds and the nature of welding.Mechanical properties testing of weld zone profiles.Study the microstructure development in the transverse weld zone use scanning electron microscopy(SEM)and electron backscattered diffraction electron microscopy(EBSD)systems.The following is the main research results of this paper.(1)"Skin tracking" technology in HyperXtrude numerical simulation software,prediction of the distribution area of transverse welds in the extrusion process of hollow aluminum alloy profiles.The prediction results of the weld distribution area are in good agreement with the actual experimental results.It provides guidance and reference for the application of numerical simulation methods to actual production.(2)The tensile fractures of the transverse weld zone specimens are basically at the transverse welds.Analyzed ot the fracture appearance by scanning electron microscopy,the results show that mostly brittle fracture of the fracture type of the material at the weld.The plasticity,strength and toughness of the materials at the transverse welds are lower than normal profiles.(3)The evolution of grain shape,special grain boundaries,and micro-textures in the transverse weld zone of the profile was studied using electron backscatter diffraction techniques.The results show that the new billet zone is mostly equiaxed grain;the old billet area is mostly elongated grain.The degree of recrystallization in the transverse welds is incomplete,mostly gram boundaries at low angles,and coarse grains affect the texture and mechanical properties of the material.In the later period of the weld,the weld becomes thin and disappears,and the grain size of both new and old materials at the two ends of the weld is more and more uniform,until they are all fine equiaxed grains.