Comparison of residual stress distributions of similar and dissimilar thick butt-weld plates

Suzuki, Hiroshi  ; Katsuyama, Jinya  ; Morii, Yukio*

Residual stress distributions of 35 mm thick dissimilar butt-weld between A533B ferritic steel and Type 304 austenitic stainless steel (304SS) with Ni alloy welds and similar metal butt-weld of 304SS were measured using neutron diffraction. Effects of differences in thermal expansion coefficients and material strengths on the weld residual stress distributions are discussed by comparison of the residual stress distributions between the similar and dissimilar metal butt-welds. Residual stresses in the similar metal butt-weld exhibited typical distributions of a thick butt-weld and they were distributed symmetrically on either side of the weld line. Meanwhile, asymmetric residual stress distributions were observed near the root region of the dissimilar metal butt-weld, which was caused by differences in thermal expansion coefficients (CTEs) and yield strengths between parent and weld metals. Transverse residual stress distribution of the dissimilar metal butt-weld was similar to that of the similar butt-weld, since effects of differences in CTEs are negligible. Magnitude of the transverse residual stress near the root region depended on the yield strengths of each metal. The normal and longitudinal residual stresses in the dissimilar metal butt-weld distributed asymmetrically on either side of weld line due to the effects of differences in CTEs.