Optimization Of Sound Parameters In Ultrasound-MIG Hybryd Welding And Research Of Drop Transition

The process of droplet transfer plays an important role on the quality ofwelded joints in the MIG. Now more and more workers begin to research thecontrol of droplet transfer.However, the droplet transfer was controlled by signal feedback regulation inthe past which was susceptible to interference by external factors. And it does nothave general applicability. The research group add ultrasonic to the weldingprocess. Then it can control droplet transition and improve the quality of joints byadjustable acoustic radiation force. The study of steel’s ultrasound-MIG weldingshows that ultrasound can facilitate the transition of the droplet, increasing thecurrent density and improve the stability of the welding process. In this paper, theultrasound-MIG welding is used for aluminum based on the previous studies.Analyzing the effect of ultrasound to arc behavior and droplet transfer. Thenoptimizing the sound field parameters and investigating the nature of ultrasound tothe droplet transition. In order to lay the foundation for the application ofultrasound-MIG lay in aluminum.First, the arc behavior of the ultrasound-MIG hybrid welding was studied. Thearc behavior was affected by the sound field parameters, the transmitter parametersand arc welding parameters. When the transmitter was in the height of resonantaltitude, the sound field had the strongest effect on the welding arc. However, theresonant height was higher than that at the room temperature. Within a certainrange, current ultrasound can enhance the effect of sound field, thus increased theamount of deformation of the arc. Meanwhile, four different transmitter’ shapeswere designed. The concave spherical, paraboloid and hyperboloid transmittercould produce a great sound pressure compared to the planar transmitter whichmade the arc the have greater change. During the four different transmitter, theconcave spherical had the greatest sound intensity. Different radio and curvature oftransmitter were also being designed, the ultrasound’s effect to arc was firstincreased then decreased along with the raising of the curvature. While it wascontinuously increasing along with the increasing of radius. Welding parametersalso had great influence on the sound filed, so choose the appropriate parameterscould gain the role od the sound field. Through the optimization of the parameters of the sound field to get a stronger sound field and process a more significant roleto the welding.Secondly, droplet transfer behavior of ultrasound-MIG was researched.Analyzing the effect of ultrasonic current and emission parameters on droplettransfer behavior from the aspects of droplet transfer frequency and shape analysis.With the increase of ultrasonic current, the size and transition frequency of dropletincrease and then remain unchanged. The changes in the shape of the emission haveno effect on droplet size, but the spherical emission can promote the transferfrequency like the arc law. Meanwhile, the ultrasound can change to mixed droplettransfer, which expanding the scope of hybrid welding. Establishing the vibrationmodel based on welding pool to analyze the reason for ulfor ultrasonic havingimpact on the morphology of seams.Again, a new method for the calculation of the acoustic radiation force wasgiven. By researching the motion of the droplet from the detachment of the wire tocontact with the bath. And then could obtain the displacement curves of dropletmovement. The motion of the droplet was in link with uniform speed. On thisaccount, it can calculate the droplet velocity and acceleration. Ultimate, thecombined force of the droplet can be obtained. By comparing the change of thecombined between normal MIG and ultrasound-MIG, and combining with thechange of the electromagnetic force, plasma flow force and gravity, then it can getthe value of the acoustic radiation force. The motion of the droplet can beconsidering as several different uniform acceleration speed motion. Throughcontrasting normal MIG and ultrasound–MIG’ acceleration trends shows thatacoustic radiation force effects on the droplet is nonlinear.Finally, the droplet transfer behavior in all-position welding of ultrasound-MIG was studied. Not all of process parameters at each location can be played onthe same effect on droplet transfer behavior. Through the experiment can determinethe suitable process parameters. Analyze the impact of ultrasound at differentlocations on the welding process through comparison of droplet transfer behavior indifferent locations.