Study On Tungsten Inert Gas Welding Assisted By Ultrasonic In T3 Copper

Aiming at the serious problem of hot cracking in copper plate during welding,the new technology-tungsten argon arc welding(GTAW)assisted by ultrasonic is put forward and used in this project.The results show that the ultrasonic-assisted GTAW can improve the quality of the weld seam and strength and avoid micro cracks,which can be regarded as a very promising method for welding.It is designed ultrasonic welding Amplitude transformer that can meet the requirements of the amplification coefficiency and work stability.The experiments were done in three different ways such as vertical,horizontal and angle variation.It is getten the regular in different ultrasonic adding ways.Through finite element analysis,it is seen the vibration characteristics in the copper plate and the amplitude rule of the ultrasonic effects,which determine the best welding position.And finally,ultrasonic –assisted GTAW is applied to the butt welding by adding HS201.Through different adding ways as vertical,horizontal and angle variation,it is explored the differences of micro-structure and performance between traditional GTAW and ultrasonic-assisted GTAW.The result shows that bulky columnar grains significantly reduced.In the welded metal,grains are refining with isometric crystals increasing.The more ultrasonic power is,the more obvious the refining effect is,the smaller radius of the crystal size has.The way ultrasonic-assisted improves and expands high temperature range.The micro-hardness and plasticity increase and the yield strength of the welds improve about 50%.The way of angle changes the direction of oneness condition that the way of vertical and horizontal have done.The vibration of the welding pool becomes complicated.It can be seen that the rule vibration of T3 copper plate by modal analysis and gets stable amplitude of surface by harmonic analysis.It is known that the surface amplitude changes with the early time of adding ultrasonic by transient analysis.The basic rule shows that amplitude increase firstly,and then tend to be stable.The amplitude in the way of angle on the early stage is not stable,finally leveles off.It is further explored the influence of ultrasonic on weld structure.By the plate welding by adding wire HS201.It is found that the way effectively inhibits the hot crack and improves joint tensile properties.Yield strength increases from 89.5 MPa to 156 MPa,increasing about 75%.Tensile strength increases from 38.9 MPa to 57.3 MPa,increased by 47%.