Comparative study of blind hole method and indentation method in measuring residual stress of 2219 aluminum alloy arc-welded joint

The residual stresses at two sides of 2219 aluminum alloy TIG weld were measured using blind hole method and indentation method, respectively. The measured points were arranged at two longitudinal sections that was 19mm away from the center line of weld. The residual stress in the aluminum alloy fusion weld approximately symmetrically distributed around the center line of weld. In this paper, the residual stresses at two sides of weld measured with two methods were compared. The results show that the change trend of measured result with two methods were consistent in general, presenting a type of parabola in the longitudinal direction of weld, i.e., the maximum value occurred in the central section of weld. According to the regression curve of two methods, the results with indentation method are about 20 MPa higher than those with blind hole method. It was found that with test of paired samples by software R, when the confidence coefficient was 0.95, the confidence interval of the difference value of two methods was (14, 37), and the mean of the differences was 25 MPa.