Research On Middle Plate Of Al-Mg Alloy Automatic Welding Process With Robotized Double-side Arc Welding

The welding process of the 5083 aluminum ally has been study,and the welding methods used in the experiment were the double TIG self-fusible welding for bottoming and the double TIG filler wire welding for filling.The welding robot station and parameter collection system have been set up in order to realize smooth operation of the robot,which is to achieve the double-side welding.The experiment studying the welding process of the robot double-side double-TIG self-fusible welding and the double-TIG filler wire welding,and the influence discipline of the process parameters,such as welding speed,energy input,has been made out.If he energy input of the self-fusible welding is in the range of 9 KJ/cm and 12.5 KJ/cm,a favorable welding joint can be achieved,and the cross section of the joint changing from an hourglass type to a square with the energy input increasing.Furthermore,the paper has also spent much time on researching how the wire feeding angle and the distance between electrode and welding wire impact the quality of the welding joint.It has been proved that the best wire feeding angle and the best wire-electrode distance are 45° and 8 mm respectively,which can make sure the molten drop of welding wire fussing into the molten bath and can effectively reduce the generation of the air hole.The comparison between the double-sided arc welding and the traditional TIG welding has been studied.The comparison includes the following four aspect:distortion after welding,the distribution of the welding temperature,the micro structure and the mechanical property.As can be seen from the experiments,the maximum distortion in height and the angle of the double-sided arc welding were only 0.185 mm and 0.69°respectively,which was only 24.2%of the traditional TIG welding.Based on the ANSYS software,the temperature field of the DSAW and the traditional TIG welding has been simulated using the heat source model which intro-duces Gaussian function.Trough analyzing the data,it has been found that a small temperature gradient,a large isotherm range,a relative high maximum temperature and uniform temperature distribution in the thickness direction exist in the temperature field of the double-sided arc welding and these properties make the DSAW have advantage in decreasing the angle distortion.The micro structure of DSAW bottoming welding mainly consists of??AI?+??Mg₂Al₃?and the crystal grain of is relatively small.It is known to all that the fragile Al-Si binary phase in the traditional TIG welding joint has a significant impact on the mechanical properties of the joint.Furthermore,the micro structure of DSAW filling welding is similar to that of the bottoming one,mainly consists of ??Al?+??Al8Mg5?,while there exists a cracked defect micro structure in the joint of singl TIG wire filling welding.However,the average tensile intensity of the double TIG is 273 MPa,which is 86.2 of that in base metal,and the elongation percentage is 81%of that in the base metal.In addition,both the tensile intensity and the elongation percentage are higher than that in join of the single TIG welding.The influence of the alternating current waveform on the air hole ratio in the joint has also been studied.With the waveform shifting to the negative direction and the energy heat increasing,the floating speed of the air bubbles rise.As a result,the number of the air holes in the joint decrease.