盲孔法与压痕法测量2219铝合金熔焊焊缝残余应力的对比分析

采用盲孔法和压痕法，分别对2219铝合金变极性TIG焊焊缝两侧的残余应力进行测量，测量点沿距焊缝中心线19 mm的纵截面上布置.铝合金熔焊的残余应力关于焊缝中心线近似对称相等，在焊缝中心线任一垂直线上，距离焊缝中心线距离相等的两点应力相等.分别用两种应力测量方法测量焊缝中心线两侧应力，对比两种测量方法对同一大小的应力测量的差别.测量结果表明，盲孔法与压痕法应力测量结果变化趋势大体一致，沿焊缝方向应力呈现抛物线状，在焊缝中部存在应力最大值.根据两种测量方法的回归曲线，压痕法测量结果比盲孔法大20 MPa左右.通过R软件做配对样本的t检验分析，在置信度为0.95时，压痕法测量结果减盲孔法测量结果的差值的置信区间为(14,37)，平均差值为25 MPa.

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.