Study On Mechanism And Process Laser-deep TIG Hybrid Welding

With the rapid development of the manufacturing industry,plate steel materials have been widely used in marine ships,tunnel excavation,construction engineering and other fields.The welding problem about the thick plates gradually received human's attention.At present,the common problem with plate welding methods is including low welding efficiency,many pre-welding preparations,and poor weld formation.Most of the welding methods need to be improved.The laser-deep TIG hybrid welding method has the effects of increasing the welding speed,reducing the heat input,and improving the weld forming.Totally,it is an efficient new welding technology.Compared with the simple deep TIG welding,the two heat sources in the laser-deep TIG welding are coupled with each other.The addition of the laser changes the existing arc-conducting channel,which has the effect of compressing and attracting the arc and enhances the arc resistance.In addition,the laser can stir the welding bath and accelerate the flow of liquid metal,which improves the weld formation.A Q345B carbon steel plate with the thick of 10mm was used as the base metal.The main parameters of the hybrid welding(Laser power PL,Welding current I,Defocus amount ?f,Heat source spacing DLA,and Arrangement method)were studied by using flat plate welding.The influence law of forming was optimized to conclude that the best defocus amount is-1mm?0mm.The best heat source space is about 0.5mm.Preposition the laser hybrid welding pattern has better effect.Two-sided molding experiments were performed on single-sided welding of 6mm thick carbon steel plates using separate deep penetration TIG welding and hybrid welding.The results show that the welding speed of hybrid welding can reach 1000mm/min,which is 3.6 times that of single deep TIG welding.The quality of the back side of the hybrid welding is better than that of the single deep-TIG welding;followed by the 10mm thick carbon steel plate,10mm thick Y-groove carbon steel plate(blunt edge 4mm,groove angle 30°),6mm thick stainless steel plate For welding.High-speed single-sided welding can be achieved on both sides of the molding process.The weld formation is good.As for the actual welding scene occurred in the group of the gap and the stagger joint of the test,the maximum tolerance of hybrid welding combination of 1mm.With a gap of+1mm,the tolerance for the stagger joint is higher than the tolerance for the gap.The microscopic observation of the laser-deep TIG welding joints were carried out to analyze the microstructure.The test of mechanical properties,such as hardness,tensile,bending,and impact were performed on the welding.All of these results satisfied the test requirements,indicating that the laser-deep fusion TIG hybrid welding joints have a good strength and toughness.