Study On Improving The Properties Of Materials And Welded Joints By Ultrasonic Impact

The welding structure is the main structural form in the industrial production.The effective reduction of the failure of the welded structure is of great significance in the industrial production.Mainly by the base metal and weld zone composed of welded structure,the control of welding residual stress and elimination can effectively reduce the occurrence of joint failure;improvement can improve the fatigue properties of materials on the surface properties of materials.As a new technology,ultrasonic peening method can effectively eliminate the residual stress of joints,and to improve the surface properties of materials,and thus enhance the reliability of the whole structure,has high application value in industrial production.In this paper,the advantages of ultrasonic peening treatment in welding residual stress are studied.The fatigue strength of the metal material before and after ultrasonic treatment was tested,which was used as a supplementary test to further explain the advanced and practical characteristics of ultrasonic peening technology.For welding specimens,mainly Q345 E low alloy steel butt joints as the research object,using the method of ultrasonic peening on residual stress were eliminated,and compared with the traditional heat treatment method,using X ray diffraction,blind hole method and indentation method three stress test method for measuring the residual stress on the fire we should try in force before and after the study,and the microstructure and mechanical properties of the joint force cancellation before and after the treatment.The test results show that the welding on Microstructure and mechanical properties of joint effect is not the case,two kinds of stress relieving method of welding residual stress elimination effect is very obvious,ultrasound impact is the residual stress change is beneficial to the joint fatigue performance of compressive stress,and near surface microhardness has significant improvement on the joint.For metal materials in annealed 304 stainless steel as the research object,on the surface of turning(Ra=0.8 m),the surface(Ra=0.2 m)ultrasonic rolling and surface electric coupling ultrasonic burnishing(Ra=0.2 m)stainless steel round bar three surface state of the bending fatigue test.The test results show that the surface of ultrasonic rolling after treatment,the average fatigue strength is turning increased by 113.5%;the surface electric coupling ultrasonic rolling processing,average turning fatigue strength is increased by 125.7%,compared with the traditional ultrasonic surface rolling treatment only increased by 5.7%.It can be seen that the ultrasonic rolling technology is very obvious to improve the fatigue performance of metal materials,while the electrical coupling of the fatigue properties of the material is not improved.