Research On Preparation,Microstructure And Properties Of High Performance 5356 Aluminum Alloy Welding Wire

5356 aluminum alloy welding wire is a general welding material with good corrosion resistance and weldability,which is widely used in every walk of life.However,the welding wire produced in China has poor surface finish,inaccurate size and bad stiffness,which cannot meet the requirements.Some industrial welding wires with high quality requirements still need to be imported,so it is necessary to study on welding wires.In this paper,the constitutive equation and thermal processing diagram are established by hot compressing the aluminum alloy wire billet with a diameter of?10mm,and the best process parameters of deformation are simulated.According to the thermal processing diagram,the temperature of 450?480?is the largest functional dissipation rate area.In order to further confirm the deformation rate,the thermally compressed samples with a deformation temperature of 450?and a deformation rate of 0.01s^-1?0.1s^-1and 1s^-1were selected to study the microstructure evolution under the electron backscattering technique.Experiments show that as the deformation rate increases,the flow stress becomes lower and lower,which is more conducive to the occurrence of dynamic recrystallization.As the deformation rate increases,geometric dynamic recrystallization occurs.When the strain rate is 0.1s^-1,the proportion of recrystallization of the billet reaches the highest,and the crystal grains are more uniform and finer.According to the hot working diagram drawn by experiments,the deformation instability area of cast-extruded?10mm wire billet is concentrated in 300?350?,and strain rate of 0.01?1s^-1.Other areas are safe.When the temperature is 430?480?,the corresponding power dissipation rate is the highest(0.35?0.38),which indicates that the thermal deformation in this area is the safest.When the deformation temperature is 450?and the deformation rate is 0.01,0.1 and 1s^-1,a"necklace"structure appears with the increase of deformation rate,the average grain size has a trend of"increasing"first,and the proportion of recrystallization area is"decreasing first and then increasing".When the strain rate is 0.01s^-1,the recrystallization ratio of wire billet reaches the highest,the machinable plasticity is the best,the grain size is more uniform and fine,and tends to be equiaxed.When the deformation temperature is450?and the deformation rate is 0.01s^-1,extruding?10mm wire billet can improve the surface finish and refine the grain size of the finished welding wire.The best annealing process for cast-extruded?6mm wire billet is 500?/2h,at which time the grains are equiaxed and the coarse grain area at the edge is smaller than other annealing temperatures;The best annealing process for continuous casting and rolling?6mm wire billet is 350?/2h.At this time,the grains are equiaxed,the coarse grain area at the edge is smaller than other annealing temperatures,and the grain size distribution at the edge and core is more uniform.Comparing the quality of?1.2mm welding wire products produced under different processes,it is found that the surface smoothness,grain size and hardness of foreign continuous casting and rolling welding wire(1#)are the best.The quality of cast-extruded welding wire(5#)and continuous casting and rolling welding wire(2#)is second,but it is better than the other two domestic welding wires.