| 5083aluminum alloy has been widely applied in modern industry，because of itshigh corrosion resistance and relatively good mechanical properties. Traditional arcwelding have some defects, such as large heat input, low efficiency, large weldingdeformation and joint softening. Laser welding is an advanced welding method, due tohigh energy density, high efficiency, low distortion and extremely low heat input. High-brightness fiber laser becoming a development direction of laser welding, for its highbeam quality, high flexibility, low running costs and easy maintenance. On account ofthe material characteristics, even with advanced laser welding, it will also have otherproblems, just like welding process instability and poor appearance of weld. Hybridlaser-arc welding technology is currently being considered as an effective weldingprocess for aluminum alloys. As an asymmetrical square-wave power supply, the dutycycle and current amplitude of the variable polarity TIG can be adjusted respectively.On the premise to meet the requirements of cathode cleaning, it can reduce thedeterioration of tungsten electrode furthest. A method of fiber laser-VPTIG hybridwelding of5083aluminum alloys integrating the advantages of the two heat sources,and make up for the deficiencies of single heat source, so the weld appearance and thequality of joint are improved.An IPG YLS-6000fiber laser and a Fronius MagicWave3000job digital weldingmachine are used in fiber laser-VPTIG hybrid welding. The experiment is carried outon the aluminum alloy5083H116with a thickness of4mm. The effect of variablepolarity parameters, arc current and distance between heat sources on weld shape ofhybrid welding are studied. The microstructure and properties of weld joints areanalyzed. The effect of wire melting process on welding stability and welding resultshave been researched. The profile and spectra of the plume and the plasma are recordedwith a high-speed camera and a spectrograph. The fundamental law of TIG arc onplume induced in high power fiber laser welding is studied, and the main mechanismof this effect is analyzed.The welding process stability and weld formation are improved while using fiberlaser-VPTIG hybrid welding. The undercut and other defects are eliminated, there areno pores and cracks in welds. The welding speed is15%higher than pure fiber laserwelding. Both the tensile strength and joint elongation are higher than fiber laser welding. Then, study on the fiber laser－VPTIG hybrid welding with wire further, theinfluence of wire feed speed and relative position between laser and wire have beeninvestigated. A stability welding process and good weld are obtained in fiber laser－VPTIG hybrid welding with wire, eliminating the sag and other defects. The tensilestrength of joint come up to331MPa, about97%of base metal, and the joint elongationis9.6%. It’s higher than fiber laser welding with wire and hybrid welding without wire.The effect of TIG arc on the plume characteristics and the welding results areinvestigated, by laser hybrid arc welding and laser－bypass arc hybrid welding. In purefiber laser welding, the plume consists of two parts, the irregularly shaped one abovethe plate and the slender shaped one along the incident laser beam, it formed by a mountof particles. TIG arc can significantly reduce the influence of the plume on incidentlaser. The main effect of TIG arc on plume is high temperature TIG arc make theparticles in plume gasification, so the influence of plume on laser beam significantlyweakened, improving the energy utilization and welding efficiency. |
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