Residual stress measurement in ultra-thick electron beam welded plate of titanium alloy
摘要
The residual stress distribution in ultra-thick plates with a single full-penetration weld is still unclear. The surface and internal residual stresses in an electron beam welded joint of 150 mm thick titanium alloy plate were both measured by coupled XRD method and inherent strain theory in this study. The 3D residual stress was obtained by collecting the inherent strain data caused by welding. It was shown that the maximal welding residual stress was the longitudinal residual stress σx. And the peak longitudinal residual stress was at the location of 50 mm below the weld surface. A heat treatment of 650℃/2 h was conducted for welding residual stress relaxation. The surface and internal residual stresses after heat treatment were both measured. It was shown that there was an obvious relaxation after heat treatment. The peak surface residual stress was reduced to 105 MPa from 535 MPa. The transverse residual stress σyc and thickness-direction residual stress σzc in the cross-sectional sample perpendicular to the weld, as well as the longitudinal residual stress σxp in the samples parallel to the weld, all approached zero.