Structure Design And Study On Gas Metal Arc Welding Torch With Arc-rotating

For the rotating arc welding, a good weld appearance can be obtained and the weld quality can be improved with arc-rotating. The rotation arc has a stirring effect to the molten pool metal. The application range of rotating arc welding is far bigger, such as thick plate welding, narrow gap welding, the space position welding, etc. At present, the torch structure had been improved and optimized, The rotating welding torch still has the disadvantage of heavy structure, complex eccentricity structure, poor economy, etc. A novel rotating arc GMAW was realized to improve the structure of the rotating arc welding torch. Owing to the arc rotation motion, the rotation arc GMAW process is very complex compared with the common GMAW. The droplet transition and arc characteristics are different compared with that of the common GMAW. Therefore, the research on the characteristic of droplet transfer, the interchangeable metal transfer and the arc stability have a great significance for analyzing its weld forming better, improving the welding stability, expanding the application range of rotating arc welding.A novel rotating arc GMAW torch was developed. The welding torch has the characteristic of sample eccentric, high control accuracy, manufacturing economy, long life and strong practicability. The maximum eccentric distance is 5 mm. The weld forming had been studied with 2mm eccentric distance. The research shows that the weld depth can be decreased and the weld width can be increased to a certain extent compared with the wire no rotation. The ratio of the weld depth and weld width decreased with the increase of the weld wire rotation speed. When the rotation speed is 40 rpm, the weld forming is very poor. The sawtooth wave shape occurs one side of the weld bead. A good weld appearance can be obtained when the rotation speed is greater than 80 rpm.Hannover welding quality analyzer and high speed camera system were used to study the characteristic of droplet transfer with different welding parameters in the welding process. The research shows that the droplet transfer mode has not been changed with the arc rotating when the transient mode is short-circuit transfer. However, the frequency of short circuit transition has been changed. The period of droplet transfer is longer in front of the molten pool than that in behind of the molten pool. In the hybrid transition zone, the way and the frequency of droplet transfer all has been changed with the arc rotating. When the current is 210 A and the voltage is 25 V, short-circuit transfer, globular transfer and projected transfer can happen in a single welding pass with the arc rotating. In the spray transition zone, the current is 240 A and the voltage is 30 V, spray transfer, projected transfer and short-circuit transfer have happened in the whole process of the droplet transfer in a period with the arc rotating speed 80 rpm. With the rotation speed increasing further, reaching 240 rpm, The droplet transfer are mainly spray transfer and projected transfer in the whole process.The welding stability also has been studied with different welding parameters. In short-circuit transfer zone and spray transfer, the welding stability is better when the arc rotating speed is high. In the hybrid transition zone with the current 210 A and voltage 25 V, the welding stability is better when the arc rotating speed is 160 rpm.The dissimilar metal welding has been made via the new Gas Metal Arc Welding torch with arc-rotating. The result shows that a good engineering application effect can be obtained.