In this study, a dominant factor influencing the weld angular distortion is discussed on the theoretical basis of the relation between weld angular distortion and distribution of inherent strain for the more accurate quantifying and managing the weld angular distortion. Focus is the mechanical melting zone as temperature distribution corresponding the generation area of inherent strain controlling the weld angular distortion. The weld angular distortions generated by TIG bead-on-plate welding under the various welding conditions were experimentally measured and then arranged by the conventional heat input parameter and the proposed parameter concerning mechanical melting zone. The mechanical melting zones were estimated through the high-accuracy welding simulation technique constructed in previous study. Based on the results, it was conˆrmed that the weld angular distortion could be quantified and managed more coordinately by the proposed parameter of mechanical melting zone rather than the conventional heat input parameter. Thus, it was concluded that the mechanical melting zone should be focused as the temperature distribution for the more accurate quantifying and managing the weld angular distortion.
In this study, a procedure for the semi-nondestructive measurement of non-equibiaxial stress field, which was developed by means of indentation technique without reference load under non-stressed state, is applied to estimate the distribution of residual stress in aluminum alloy welds. The procedure requires two constants for stress determination. One is the ratio of indentation load between Knoop and Vickers indenters, and the other is the conversion factor determining the relation between residual stress and change of indentation load due to the residual stress. They were experimentally quantified and then the distribution of weld residual stress was measured by the developed procedure using indentation technique. The measurement result was compared with those estimated by various other stress measurement techniques of X-ray di−raction and stress relief methods, and numerical simulation developed in previous study. As the results, it was conˆrmed that the developed stress measurement technique using indentation technique provided good agreement with other stress estimation techniques. Thus, the developed procedure using indentation technique is expected to be a useful semi-nondestructive technique for estimating the residual stress in aluminum alloy welds.