Residual Stress Measurement On Q345R Rolling Welding Vessel With The Electromagnetic Ultrasonic Method

The existence of welding residual stress will severely affect the performance of the structure.Therefore,it is of great significance to measure and analyze the distribution of the welding residual stress to ensure the safety of the welded structure.The electromagnetic ultrasonic method is an emerging means in measuring residual stress,which has the advantages of being efficient,non-destructive,and no need of coupling agent.In this paper,the electromagnetic ultrasonic method is used to measure the welding residual stress on the rolling welding vessel,and the measurement results are verified and compared by the measurement of blind hole method and finite element simulation.The results indicate that the electromagnetic ultrasonic method can effectively measure the average stress in the thickness direction on the vessel,which has certain engineering value.The main work carried out is listed as follows:(1)Electromagnetic ultrasonic method was used to measure the residual stress of Q345 R rolling welding vessel.The anisotropy parameters of the material were introduced to revise the current acoustic elasticity equation.Then the acoustic elastic coefficients and anisotropy parameters of the weld zone,heat-affected zone,and base metal zone were calibrated under normal temperature environment(25±2?).Combining with the ultrasonic velocity measured by electromagnetic ultrasonic equipment,the residual stress distribution of the welding vessel made of Q345 R was obtained through conversion.(2)The blind hole method was utilized for the residual stress detection of the welding vessel the and the measurements were used to verify the results of electromagnetic ultrasonic method.The strain relief coefficient after plastic correction was used to calculate the measurement results,which were contrasted with the stress obtained by electromagnetic ultrasonic means.It shows a good consistency between the results by two methods,but there are certain deviations in specific values.(3)Based on the thermal elastic-plastic analysis method,the residual stress of the welding vessel was simulated and calculated to verify the results of electromagnetic ultrasonic method.The finite element model was established and the Simufact.Welding software was used to simulate the stress of the vessel.Then the Abaqus software was used to simulate the residual stress of the plate after rolling by the four rollers board machine.The above calculation results were compared with the measurements of the blind hole method and the finite element model of the welding vessel was verified.The simulation results were compared with the measurements of the electromagnetic ultrasonic method.The comparison results show that the distribution trends of residual stress gained by two methods are basically the same.In the area of 400-600 mm from the girth weld,most relative errors of the axial stress are within 21% in the base metal zone(path Z3).