The Numerical Simulation Research Of Ultrasonic Impact Treatment On Welding Residual Shtess

The welding process is carried on local region of weldment and inevitably will cause the complex welding residual stress.The welds residual stress affects the welding structure performance,the security reliability and the manufacture technological,which has the very disadvantageous influence to the quality of the welding structure.So it is one of the important issues which must be solved in the welding structure production process.There are many factors influencing the welding residual stress,such as the welding sequence,the weld size,the post-weld treatment(such as TIG melting repair,Ultrasonic Impact Treatment(UIT))etc.Therefore,the different welding process will cause different stress distribution to the welded structure.There must be a procedure to the best quality of the welded structure.In this paper,MSC.MARC was used to calculate the welding residual stress of the belt shape of cup penetration under different welding procedures.How the residual stress transform when the factors above-mentioned changed was discussed according to the calculated result.Stress data indicated that the alternate welding,the large seam shape,TIG melting repair only affect the stress of two directions,the transverse,the depth of fusion.Compared with the respective comparison object,in the transverse of fusion direction,the stress peak values was decreased 15%,26% and 26.7%(small seam shape,TIG melting repair),6.6%(large seam shape,TIG melting repair);In the depth of fusion direction,the stress peak values was decreased 4%,20% separately and 17.4%(small seam shape,TIG melting repair),9.4%(large seam shape,TIG melting repair).UIT reduced the stress of the transverse,the depth of fusion and the Longitudinal.After the UIT,the stress peak of the three directions dropped 31.7%,10% and 10%.And it also transferred the most dangerous locations of the stress to the internal weld.That improved the welding site stress distinctly.This was benefit to the fatigue properties of the structure.According to these analysis,it revealed that the best welding process of the belt shape of cup penetration.It`s better to select the best group of large seam shape,alternate welding,TIG melting repair and Ultrasonic Impact Treatment(UIT)to obtain the stress modulated.