Study On Technology And Narrow Gap Application Of Swing TIG-MIG Hybrid Welding

TIG-MIG hybrid welding is a new type of hybrid welding method that combines the advantages of high quality of TIG welding head and the high efficiency of MIG welding.It exhibits the advantages of high efficiency and high quality and has a wide range of application prospects.However,TIG-MIG cannot solve the problem of poor fusion of narrow gap welding sidewalls.In order to improve the application of the TIG-MIG hybrid welding method in narrow gap welding,this project proposed a swing TIG-MIG hybrid welding method on the basis of the TIG-MIG hybrid welding method.It was found that this method can significantly improve the weld spread and the quality of welds;not only successful in narrow gap welding,but also in flat welding,compared with other welding methods also have certain advantages.This paper introduced the basic principle of the swing TIG-MIG hybrid welding,and in order to verify the reliability of the new welding method,process characteristics and the feasibility of the narrow gap welding,we set up a swing TIG-MIG hybrid welding experimental system,through theoretical analysis and related experiments,to verify the feasibility and effectiveness of the proposed method.Swing TIG-MIG hybrid welding experimental system includes welding system,current and voltage acquisition system,video acquisition system and thermal signal acquisition system.Welding s ystems mainly include welding table and welding equipment.The welding table includes a motion control device and a welding torch fixing device.Based on the constructed experimental system,the characteristics of the swing TIG-MIG hybrid welding were introduced.The arc shape was acquired with the help of the image acquisition system.The current and voltage were collected with the current and voltage acquisition system.By the method of swing TIG-MIG hybrid welding method,the surfacing welding experiment was conducted on a flat plate to study the effect of changes in welding parameters on the weld formation.The welding parameters mainly included TIG current,MIG current,welding speed,and swing frequency.The results showed that the swing TIG-MIG hybrid welding method is better than TIG-MIG hybrid welding on weld formation.Swing TIG-MIG composite welding can effectively increase weld width and weld spread,improve weld formation,reduce undercut and other defects,and improve weld quality.The swing of the TIG welding torch plays an important role in the formation of the weld seam.It is the reason that the swing TIG-MIG hybrid welding is better than the TIG-MIG hybrid welding.The swing of the TIG welding torch can obviously change the width of the TIG weld;and with the increase of the swing frequency,the boundary of the weld becomes more flat;and when the welding speed is fixed,the effect of the swing frequency on the appearance of the TIG weld pool is firs increased and then reduced.In the TIG welding,the swing of the TIG welding torch has little interference with the TIG welding current and voltage;In the TIG-MIG hybrid welding,two arcs interfere with each other and cause changes in the TIG and MIG current and voltage.It was found that the voltage change map of the swing TIG-MIG is similar to that of the TIG-MIG,so it can be inferred that the swing TIG-MIG has the same arc interference as the TIG-MIG,but the influence of the swing of the TIG welding on the MIG welding current and voltage is very small.The TIG welding torch swings periodically and oscillatingly,and the TIG arc combustion in the swing TIG-MIG hybrid welding is stable.And in swing TIG-MIG hybrid welding,in order to improve weld spread and reduce defects such as undercut,the swing width of TIG welding torch in swing TIG-MIG welding should exceed the weld width of TIG-MIG hybrid welding.Under certain welding parameters,The width of the weld increases with the increase of the MIG welding current,and the height of the weld seam does not change.With a certain welding parameter,as the welding current of the TIG increases,the width of the weld increases,and the height of weld seam increases continuously.When the welding parameters are constant,the width of the weld seam is s maller with the increase of the wobble frequency,and the height of weld seam is increased.With a certain welding parameter,as the welding speed increases,the height of weld seam is basically maintained invariable,the width of the weld seam continues t o decrease;The effect of the weld seam improvement depends on the coordination of the TIG welding current,the oscillation frequency,and the welding speed.The study of narrow gap welding was carried out using the swing TIG-MIG hybrid welding method;the feasibility and forming characteristics of the swing TIG-MIG hybrid welding in narrow gap welding were studyed.The experiment found that the swing TIG-MIG hybrid welding method can be used in narrow gap welding and the weld formation is good.And in the swing TIG-MIG hybrid welding,TIG welding torch can not only improve the sidewall fusion,but also can preheat the MIG welding wire,increase the melting speed of the welding wire,and thus greatly increase the welding speed.Compared with other narrow gap welding methods,the narrow gapswing MIG-TIG hybrid welding method has the advantages of high efficiency and high quality.During the swing TIG-MIG narrow gap welding process,attention should be paid to the size of the narrow gap TIG current and select t he matching MIG welding wire feed speed according to the TIG current,to prevent the MIG arc starts on the sidewall during the welding process and affect the quality of the weld.In the swing TIG-MIG hybrid welding method,the TIG arc periodically swings as the TIG torch swings.This is different from the arc swinging in the flat welding,the TIG arc is blocked by the two sides of the weld during the narrow gap welding process.The arc comes into contact with the side walls,causing the side walls melting.