Detection And Evaluation Of The Plastic Deformation Of Weld Joint By Nonlinear Ultrasonic Technique

Welded joints are widely applied in petrochemical industry and nuclear power, etc. How to keep welded components operating safety is a challenging task. It’s important to establish effective methods for evaluation of the healthy state of materials and prediction of their remaining life. The nonlinear ultrasonic technique has been found recently to evaluate to the performance degradation of materials or components in the early working-time.Continuing and interrupted tensile tests were conducted for A17009.The measurement results show little differences, but with a similar trend. The nonlinear parameter increases with increasing the plastic strain.The welded joint of30Cr2Ni4MoV steel was studied in terms of nonlinear ultrasonic, velocity and attenuation measurements. These results show:(a) The nonlinear parameter is increase with increasing the plastic strain. Among the measurement locations, the nonlinear parameter displays a maximum change at the middle position of the welding line.(b)There is no obvious repeated relationship between the ultrasonic velocity and the plastic strain.(c)There is no obvious repeated relationship between the attenuation and the plastic strain,(d) Comparing with conventional ultrasonic methods, the nonlinear ultrasonic method is more suitable for evaluating the performance degradation of30Cr2Ni4MoV welded joint.Moreover, the microstructures of the welding line were analyzed based on metallographic studies for interpreting the relationship between the nonlinear parameter and the plastic deformation.