Numerical Simulation On Welding Residual Stresses Of The X80 Pipeline Steel Based On USRP

Ultrasonic surface rolling processing is a new surface hardening technology,which based on severe plastic deformation in the surface layer.The introduce of residual compressive stress and work hardening on surface will significantly improve the fatigue strength and the resistance to stress corrosion of workpieces.Using ABAQUS,a software for finite element analysis,the numerical simulation of USRP has been completed.To get the distribution curves of residual stress and equivalent plastic strain,one path along the thickness direction was created,and five processing parameters were take turns to change,which include descending distance,static pressure,friction coefficient,ball diameter and processing times.To compare the distribution curves of equivalent stress under two different loading methods,descending distance and static pressure,research are verified that the USRP between ball and workpieces are different under two loading methods.In this paper,taking X80 steel as the research object,the residual stress of welding using finite element analysis method was studied.Firstly the distribution of X80 steel welding temperature field is gotten by ABAQUS software,and then the welding thermal analysis results are used for the next stress analysis to obtain the distribution of welding residual stress.In the simulation,the influence of the second welding on the residual stress of the first welding in the double welding and the influences of different heat source power and welding speed on the size and distribution of welding residual stress using double ellipsoid heat source model are studied.A 3D finite element model about ultrasonic surface rolling process was established,and the model was analyzed by means of the finite element software ABAQUS.A moving double ellipsoid welding heat source were developed,and the residual stresses before and after the treatment of USRP are obtained.Effects of multiple impacts were considered during the simulation.The results show that due to the application of USRP,the compressive stresses aregenerated in the weld metal,along with the increase of the coverage,the compressive residual stress increases,proving that the USRP could reduce weld residual stress.In order to verify the accuracy of the X80 pipeline steel and its welded joint numerical simulation after USRP.Verify the accuracy of the numerical simulation using the piece-cutting method.The results compared favorably with the experimental result.