抄録
Residual stress profiles of multi layer butt joint specimen were analytically and experimentally studied. A steel used in this study was the low alloy steel SQV2A (JIS G 3120), which is equivalent to ASTM A533. Phase transformation occurs in the welding pass area of SQV2A and affects the residual stress profiles. To estimate the residual stress profiles numerically, temperature history analysis and residual stress analysis were conducted. Phase transformation strain was taken into consideration as a component of thermal strain. Analysis without phase transformation strain was also conducted to determine effect of the phase transformation strain on residual stress analysis results. Analysis result with phase transformation strain consideration shows that the amount of longitudinal stress at the welded area on each surface of the specimen is 200 MPa, which is lower than yield stress of the steel. In contrast, analysis result without phase transformation strain consideration shows that the amount of longitudinal stress in the welded area on each surface of the specimen is yield stress. To validate the analysis results, residual stress on the surface of the specimen was measured by using the strain relief method. The analysis results with the phase transformation strain are in agreement with the experiment results. Accordingly, the analysis results with phase transformation strain can be considered valid.
