Investigation of Residual Stresses Distribution in Titanium Weldments

Abstract

Titanium and its alloys have increasingly become a material of choice for applications in high-performance structures due to their superior corrosion resistance and high strength-to-weight ratio. However, in contrast to conventional steel alloys, there exist little design and manufacturing experience in the heavy fabrication industry with large welded structures made of titanium materials. In addressing the above concern, the University of New Orleans funded by Office of Naval Research (ONR) initiated program on investigation of manufacturability and performance of a titanium mid-ship section. The uniqueness of this program is its focus upon a representative full-size mid-ship section upon which relevant scientific and technological challenges are simulated and experimentally validated. This paper reports the measurements of residual stresses using neutron diffraction in titanium T-joints. The residual stresses were measured using Engin-X at ISIS (UK) and the Kowari Strain Scanner at ANSTO (Australia). This experimental research was used to validate our in house predictions and significantly improved the knowledge and understanding of the welding process of titanium alloys.

An Overview of TIG Welding of Ti6Al4V: Recent Developments

“…Pulsed current TIG welding has also mitigated the level of residual stresses within the WZ because of controlled heat input used in this technique compared to the unpulsed TIG welding [74]. Song et al [89] observed longitudinal stresses in Ti6Al4V alloy plates of 6 mm, measured at 1.6 mm below the surface of the workpiece to have the largest tensile stress within the weld area and small compressive strength outside the weld area. At a current of 170 A, Reda et al [22] observed residual stress of 71 MPa for a 12 mm thick Ti6Al4V alloy plate, longitudinal compressive stresses were also observed in the plates, with magnitudes smaller than the tensile stresses in the FZ, while the transverse residual stresses developed within the FZ are smaller than that of the longitudinal residual stresses.…”